'getIncludedPages' in class com.xpn.xwiki.api.Document threw java.lang.NullPointerException

On some pages i got an exception in the document info panel when editing a page and also on the document information tab of the page i got this error:

org.xwiki.rendering.macro.MacroExecutionException: Failed to evaluate Velocity Macro for content [$xwiki.ssx.use('Panels.DocumentInformation')##
#set ($pages = $tdoc.includedPages)
#largepanelheader($msg.get('panels.documentInformation.title'))
#if ($tdoc.language == '' && $xwiki.isMultiLingual())
; html<label for="xwikidoclanguageinput2">$msg.get('panels.documentInformation.defaultLanguage')</label>/html
: html<input type="text" id="xwikidoclanguageinput2" name="defaultLanguage" value="$!tdoc.defaultLanguage" size="30"/>/html
#end
##--------------------------------------------------------------------------

1. 1. Display wiki syntax combo box if there's more than one configured syntax.
      ##--------------------------------------------------------------------------
      $xwiki.jsx.use($paneldoc.fullName)##
      #if ($xwiki.getConfiguredSyntaxes().size() > 1)
      ; html<label for="xwikidocsyntaxinput2">$msg.get('panels.documentInformation.syntax')</label>/html
      : html<select name="syntaxId" id="xwikidocsyntaxinput2">
      <option value="xwiki/1.0"#if ($tdoc.getSyntax().toIdString().equalsIgnoreCase('xwiki/1.0')) selected="selected"#end>XWiki 1.0</option>
      #set ($configuredSyntaxes = $xwiki.getConfiguredSyntaxes())
      ##
   2. Starting with XE 2.3 the $syntaxFactory binding has been removed and the new $services binding added.
   3. To make sure this Panel application still work with versions less than 2.3 we verify the availability of bindings.
      #set ($availableParserSyntaxes = $services.rendering.getAvailableParserSyntaxes())
      #if (!$availableParserSyntaxes)
      #set ($availableParserSyntaxes = $syntaxFactory.getAvailableSyntaxes())
      #end
      ##
      #foreach ($syntax in $availableParserSyntaxes)
      #if ($configuredSyntaxes.contains($syntax.toIdString()) && !$syntax.toIdString().equalsIgnoreCase('xwiki/1.0'))
      <option value="$syntax.toIdString()"#if($tdoc.getSyntax().toIdString().equalsIgnoreCase($syntax.toIdString())) selected="selected"#end>$syntax.toString()</option>
      #end
      #end
      </select>/html
      #end
      ##--------------------------------------------------------------------------
      #if($pages.size() != 0)
      ; $msg.get('panels.documentInformation.includesCount', [$pages.size()])
      #foreach ($page in $pages)
      : [[$page>>$page]] [[[[image:icon:page_white_edit||alt="$msg.get('panels.documentInformation.editIncluded', [$page])"]]>>path:$xwiki.getURL($page, 'edit')]]
      #end
      #end
      #panelfooter()]
      at org.xwiki.rendering.internal.macro.velocity.VelocityMacro.evaluateString(VelocityMacro.java:131)
      at org.xwiki.rendering.internal.macro.velocity.VelocityMacro.evaluateString(VelocityMacro.java:50)
      at org.xwiki.rendering.macro.script.AbstractScriptMacro.evaluateBlock(AbstractScriptMacro.java:302)
      at org.xwiki.rendering.macro.script.AbstractScriptMacro.execute(AbstractScriptMacro.java:198)
      at org.xwiki.rendering.macro.script.AbstractScriptMacro.execute(AbstractScriptMacro.java:59)
      at org.xwiki.rendering.internal.transformation.macro.MacroTransformation.transformOnce(MacroTransformation.java:187)
      at org.xwiki.rendering.internal.transformation.macro.MacroTransformation.transform(MacroTransformation.java:132)
      at org.xwiki.rendering.internal.transformation.DefaultTransformationManager.performTransformations(DefaultTransformationManager.java:83)
      at org.xwiki.display.internal.DocumentContentDisplayer.display(DocumentContentDisplayer.java:248)
      at org.xwiki.display.internal.DocumentContentDisplayer.display(DocumentContentDisplayer.java:124)
      at org.xwiki.display.internal.DocumentContentDisplayer.display(DocumentContentDisplayer.java:54)
      at org.xwiki.display.internal.DefaultDocumentDisplayer.display(DefaultDocumentDisplayer.java:80)
      at org.xwiki.display.internal.DefaultDocumentDisplayer.display(DefaultDocumentDisplayer.java:38)
      at com.xpn.xwiki.internal.sheet.SheetDocumentDisplayer.display(SheetDocumentDisplayer.java:113)
      at com.xpn.xwiki.internal.sheet.SheetDocumentDisplayer.display(SheetDocumentDisplayer.java:57)
      at org.xwiki.display.internal.ConfiguredDocumentDisplayer.display(ConfiguredDocumentDisplayer.java:67)
      at org.xwiki.display.internal.ConfiguredDocumentDisplayer.display(ConfiguredDocumentDisplayer.java:41)
      at com.xpn.xwiki.doc.XWikiDocument.getRenderedContent(XWikiDocument.java:918)
      at com.xpn.xwiki.doc.XWikiDocument.getRenderedContent(XWikiDocument.java:884)
      at com.xpn.xwiki.objects.classes.TextAreaClass.displayView(TextAreaClass.java:235)
      at com.xpn.xwiki.doc.XWikiDocument.display(XWikiDocument.java:2810)
      at com.xpn.xwiki.doc.XWikiDocument.display(XWikiDocument.java:2771)
      at com.xpn.xwiki.doc.XWikiDocument.display(XWikiDocument.java:2720)
      at com.xpn.xwiki.api.Document.display(Document.java:1248)
      at sun.reflect.GeneratedMethodAccessor326.invoke(Unknown Source)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
      at java.lang.reflect.Method.invoke(Unknown Source)
      at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.doInvoke(UberspectImpl.java:395)
      at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.invoke(UberspectImpl.java:384)
      at org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:173)
      at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:280)
      at org.apache.velocity.runtime.parser.node.ASTReference.render(ASTReference.java:369)
      at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:72)
      at org.apache.velocity.runtime.parser.node.ASTIfStatement.render(ASTIfStatement.java:87)
      at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:72)
      at org.apache.velocity.runtime.parser.node.ASTIfStatement.render(ASTIfStatement.java:87)
      at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:72)
      at org.apache.velocity.runtime.directive.VelocimacroProxy.render(VelocimacroProxy.java:216)
      at org.apache.velocity.runtime.directive.RuntimeMacro.render(RuntimeMacro.java:311)
      at org.apache.velocity.runtime.directive.RuntimeMacro.render(RuntimeMacro.java:230)
      at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:207)
      at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:72)
      at org.apache.velocity.runtime.directive.Foreach.render(Foreach.java:420)
      at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:207)
      at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:72)
      at org.apache.velocity.runtime.parser.node.ASTIfStatement.render(ASTIfStatement.java:87)
      at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:342)
      at org.xwiki.velocity.internal.DefaultVelocityEngine.evaluate(DefaultVelocityEngine.java:186)
      at org.xwiki.velocity.internal.DefaultVelocityEngine.evaluate(DefaultVelocityEngine.java:152)
      at com.xpn.xwiki.render.XWikiVelocityRenderer.evaluate(XWikiVelocityRenderer.java:117)
      at com.xpn.xwiki.XWiki.evaluateTemplate(XWiki.java:1813)
      at com.xpn.xwiki.XWiki.parseTemplate(XWiki.java:1750)
      at com.xpn.xwiki.api.XWiki.parseTemplate(XWiki.java:839)
      at sun.reflect.GeneratedMethodAccessor170.invoke(Unknown Source)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
      at java.lang.reflect.Method.invoke(Unknown Source)
      at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.doInvoke(UberspectImpl.java:395)
      at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.invoke(UberspectImpl.java:384)
      at org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:173)
      at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:280)
      at org.apache.velocity.runtime.parser.node.ASTReference.render(ASTReference.java:369)
      at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:72)
      at org.apache.velocity.runtime.directive.VelocimacroProxy.render(VelocimacroProxy.java:216)
      at org.apache.velocity.runtime.directive.RuntimeMacro.render(RuntimeMacro.java:311)
      at org.apache.velocity.runtime.directive.RuntimeMacro.render(RuntimeMacro.java:230)
      at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:207)
      at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:72)
      at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:342)
      at org.apache.velocity.runtime.parser.node.ASTIfStatement.render(ASTIfStatement.java:106)
      at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:72)
      at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:342)
      at org.apache.velocity.runtime.parser.node.ASTIfStatement.render(ASTIfStatement.java:106)
      at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:342)
      at org.xwiki.velocity.internal.DefaultVelocityEngine.evaluate(DefaultVelocityEngine.java:186)
      at org.xwiki.velocity.internal.DefaultVelocityEngine.evaluate(DefaultVelocityEngine.java:152)
      at com.xpn.xwiki.render.XWikiVelocityRenderer.evaluate(XWikiVelocityRenderer.java:117)
      at com.xpn.xwiki.XWiki.evaluateTemplate(XWiki.java:1813)
      at com.xpn.xwiki.web.Utils.parseTemplate(Utils.java:154)
      at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:239)
      at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:116)
      at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
      at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
      at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
      at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414)
      at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
      at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
      at com.xpn.xwiki.web.ActionFilter.doFilter(ActionFilter.java:128)
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
      at org.xwiki.wysiwyg.server.filter.ConversionFilter.doFilter(ConversionFilter.java:144)
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
      at com.xpn.xwiki.plugin.webdav.XWikiDavFilter.doFilter(XWikiDavFilter.java:68)
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
      at org.xwiki.container.servlet.filters.internal.SavedRequestRestorerFilter.doFilter(SavedRequestRestorerFilter.java:217)
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
      at org.xwiki.container.servlet.filters.internal.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:109)
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
      at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
      at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
      at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
      at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
      at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
      at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
      at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:857)
      at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
      at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
      at java.lang.Thread.run(Unknown Source)
      Caused by: org.xwiki.velocity.XWikiVelocityException: Failed to evaluate content with id [xwiki:MySpace.MyDoc]
      at org.xwiki.velocity.internal.DefaultVelocityEngine.evaluate(DefaultVelocityEngine.java:195)
      at org.xwiki.velocity.internal.DefaultVelocityEngine.evaluate(DefaultVelocityEngine.java:152)
      at org.xwiki.rendering.internal.macro.velocity.VelocityMacro.evaluateString(VelocityMacro.java:124)
      ... 112 more
      Caused by: org.apache.velocity.exception.MethodInvocationException: Invocation of method 'getIncludedPages' in class com.xpn.xwiki.api.Document threw exception java.lang.NullPointerException at xwiki:MySpace.MyDoc[line 2, column 22]
      at org.apache.velocity.runtime.parser.node.ASTIdentifier.execute(ASTIdentifier.java:223)
      at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:280)
      at org.apache.velocity.runtime.parser.node.ASTReference.value(ASTReference.java:567)
      at org.apache.velocity.runtime.parser.node.ASTExpression.value(ASTExpression.java:71)
      at org.apache.velocity.runtime.parser.node.ASTSetDirective.render(ASTSetDirective.java:142)
      at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:342)
      at org.xwiki.velocity.internal.DefaultVelocityEngine.evaluate(DefaultVelocityEngine.java:186)
      ... 114 more
      Caused by: java.lang.NullPointerException
      at com.xpn.xwiki.doc.XWikiDocument.getIncludedPages(XWikiDocument.java:4795)
      at com.xpn.xwiki.api.Document.getIncludedPages(Document.java:1310)
      at sun.reflect.GeneratedMethodAccessor556.invoke(Unknown Source)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
      at java.lang.reflect.Method.invoke(Unknown Source)
      at org.apache.velocity.runtime.parser.node.PropertyExecutor.execute(PropertyExecutor.java:142)
      at org.apache.velocity.util.introspection.UberspectImpl$VelGetterImpl.invoke(UberspectImpl.java:539)
      at org.apache.velocity.runtime.parser.node.ASTIdentifier.execute(ASTIdentifier.java:198)
      ... 120 more