Exporting multiple pages to PDF or RTF generates exception

Rather than generating a file i get the following page when exporting multiple pages to PDF:

%PDF-1.4 %ª«¬

When exporting the same set of pages to RTF i get an empty page, in stead of the expected RTF file.

No logging shows up in case of exporting to RTF, exporting to PDF generates the following trace:

12:33:28,357 [P1-17] WARN web.XWikiAction - Uncaught exception: Error number 11015 in 11: Exception while exporting
Wrapped Exception: Error number 12002 in 12: Exception while exporting PDF
Wrapped Exception: org.apache.fop.fo.ValidationException: null:552:257: Property id "HIDE" previously used; id values must be unique in document.
com.xpn.xwiki.XWikiException: Error number 11015 in 11: Exception while exporting
Wrapped Exception: Error number 12002 in 12: Exception while exporting PDF
Wrapped Exception: org.apache.fop.fo.ValidationException: null:552:257: Property id "HIDE" previously used; id values must be unique in document.
at com.xpn.xwiki.web.ExportAction.render(ExportAction.java:53)
at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:148)
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:596)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:428)
at org.mortbay.jetty.servlet.WebApplicationHandler$CachedChain.doFilter(WebApplicationHandler.java:830)
at com.xpn.xwiki.web.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:117)
at org.mortbay.jetty.servlet.WebApplicationHandler$CachedChain.doFilter(WebApplicationHandler.java:821)
at org.mortbay.jetty.servlet.WebApplicationHandler.dispatch(WebApplicationHandler.java:471)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:568)
at org.mortbay.http.HttpContext.handle(HttpContext.java:1565)
at org.mortbay.jetty.servlet.WebApplicationContext.handle(WebApplicationContext.java:633)
at org.mortbay.http.HttpContext.handle(HttpContext.java:1517)
at org.mortbay.http.HttpServer.service(HttpServer.java:954)
at org.mortbay.http.HttpConnection.service(HttpConnection.java:816)
at org.mortbay.http.HttpConnection.handleNext(HttpConnection.java:983)
at org.mortbay.http.HttpConnection.handle(HttpConnection.java:833)
at org.mortbay.http.SocketListener.handleConnection(SocketListener.java:244)
at org.mortbay.util.ThreadedServer.handle(ThreadedServer.java:357)
at org.mortbay.util.ThreadPool$PoolThread.run(ThreadPool.java:534)

Wrapped Exception:

com.xpn.xwiki.XWikiException: Error number 12002 in 12: Exception while exporting PDF
Wrapped Exception: org.apache.fop.fo.ValidationException: null:552:257: Property id "HIDE" previously used; id values must be unique in document.
at com.xpn.xwiki.pdf.impl.PdfExportImpl.exportXMLFO(PdfExportImpl.java:182)
at com.xpn.xwiki.pdf.impl.PdfExportImpl.exportXHtml(PdfExportImpl.java:126)
at com.xpn.xwiki.pdf.impl.PdfExportImpl.exportHtml(PdfExportImpl.java:190)
at com.xpn.xwiki.pdf.impl.PdfExportImpl.export(PdfExportImpl.java:206)
at com.xpn.xwiki.web.ExportAction.exportPDFOrRTF(ExportAction.java:82)
at com.xpn.xwiki.web.ExportAction.render(ExportAction.java:50)
at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:148)
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:596)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:428)
at org.mortbay.jetty.servlet.WebApplicationHandler$CachedChain.doFilter(WebApplicationHandler.java:830)
at com.xpn.xwiki.web.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:117)
at org.mortbay.jetty.servlet.WebApplicationHandler$CachedChain.doFilter(WebApplicationHandler.java:821)
at org.mortbay.jetty.servlet.WebApplicationHandler.dispatch(WebApplicationHandler.java:471)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:568)
at org.mortbay.http.HttpContext.handle(HttpContext.java:1565)
at org.mortbay.jetty.servlet.WebApplicationContext.handle(WebApplicationContext.java:633)
at org.mortbay.http.HttpContext.handle(HttpContext.java:1517)
at org.mortbay.http.HttpServer.service(HttpServer.java:954)
at org.mortbay.http.HttpConnection.service(HttpConnection.java:816)
at org.mortbay.http.HttpConnection.handleNext(HttpConnection.java:983)
at org.mortbay.http.HttpConnection.handle(HttpConnection.java:833)
at org.mortbay.http.SocketListener.handleConnection(SocketListener.java:244)
at org.mortbay.util.ThreadedServer.handle(ThreadedServer.java:357)
at org.mortbay.util.ThreadPool$PoolThread.run(ThreadPool.java:534)

Wrapped Exception:

org.apache.fop.fo.ValidationException: null:552:257: Property id "HIDE" previously used; id values must be unique in document.
at org.apache.fop.fo.FObj.checkId(FObj.java:157)
at org.apache.fop.fo.flow.Inline.startOfNode(Inline.java:102)
at org.apache.fop.fo.FOTreeBuilder$MainFOHandler.startElement(FOTreeBuilder.java:330)
at org.apache.fop.fo.FOTreeBuilder.startElement(FOTreeBuilder.java:185)
at org.apache.xalan.transformer.TransformerIdentityImpl.startElement(TransformerIdentityImpl.java:1042)
at org.apache.xerces.parsers.AbstractSAXParser.startElement(AbstractSAXParser.java:454)
at org.apache.xerces.impl.XMLNamespaceBinder.handleStartElement(XMLNamespaceBinder.java:876)
at org.apache.xerces.impl.XMLNamespaceBinder.startElement(XMLNamespaceBinder.java:568)
at org.apache.xerces.impl.dtd.XMLDTDValidator.startElement(XMLDTDValidator.java:756)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanStartElement(XMLDocumentFragmentScannerImpl.java:752)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl$FragmentContentDispatcher.dispatch(XMLDocumentFragmentScannerImpl.java:1453)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:333)
at org.apache.xerces.parsers.DTDConfiguration.parse(DTDConfiguration.java:524)
at org.apache.xerces.parsers.DTDConfiguration.parse(DTDConfiguration.java:580)
at org.apache.xerces.parsers.XMLParser.parse(XMLParser.java:152)
at org.apache.xerces.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1169)
at org.apache.xalan.transformer.TransformerIdentityImpl.transform(TransformerIdentityImpl.java:463)
at com.xpn.xwiki.pdf.impl.PdfExportImpl.exportXMLFO(PdfExportImpl.java:151)
at com.xpn.xwiki.pdf.impl.PdfExportImpl.exportXHtml(PdfExportImpl.java:126)
at com.xpn.xwiki.pdf.impl.PdfExportImpl.exportHtml(PdfExportImpl.java:190)
at com.xpn.xwiki.pdf.impl.PdfExportImpl.export(PdfExportImpl.java:206)
at com.xpn.xwiki.web.ExportAction.exportPDFOrRTF(ExportAction.java:82)
at com.xpn.xwiki.web.ExportAction.render(ExportAction.java:50)
at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:148)
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:596)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:428)
at org.mortbay.jetty.servlet.WebApplicationHandler$CachedChain.doFilter(WebApplicationHandler.java:830)
at com.xpn.xwiki.web.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:117)
at org.mortbay.jetty.servlet.WebApplicationHandler$CachedChain.doFilter(WebApplicationHandler.java:821)
at org.mortbay.jetty.servlet.WebApplicationHandler.dispatch(WebApplicationHandler.java:471)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:568)
at org.mortbay.http.HttpContext.handle(HttpContext.java:1565)
at org.mortbay.jetty.servlet.WebApplicationContext.handle(WebApplicationContext.java:633)
at org.mortbay.http.HttpContext.handle(HttpContext.java:1517)
at org.mortbay.http.HttpServer.service(HttpServer.java:954)
at org.mortbay.http.HttpConnection.service(HttpConnection.java:816)
at org.mortbay.http.HttpConnection.handleNext(HttpConnection.java:983)
at org.mortbay.http.HttpConnection.handle(HttpConnection.java:833)
at org.mortbay.http.SocketListener.handleConnection(SocketListener.java:244)
at org.mortbay.util.ThreadedServer.handle(ThreadedServer.java:357)
at org.mortbay.util.ThreadPool$PoolThread.run(ThreadPool.java:534)