CB >3 folder created. Clicked Select link of F2 throws an Error.

Create a collection.
click Edit link.
In CB, click Build Up.
Select folder option and create a folder ( say F1)
Click Build Up button below F1.
Select folder option and create a folder ( say F2)
Click Build Up button below F2.
Select folder option and create a folder ( say F3)

now in TOC, click F1 and then click Select link of F2.
the follwoing Error is thrown:

Error number 0 in 19: Unknown GWT Exception Wrapped Exception: null com.xpn.xwiki.XWikiException: Error number 0 in 19: Unknown GWT Exception Wrapped Exception: null at com.xpn.xwiki.gwt.api.server.XWikiServiceImpl.getXWikiGWTException(XWikiServiceImpl.java:188) at com.xpn.xwiki.gwt.api.server.XWikiServiceImpl.getDocument(XWikiServiceImpl.java:255) at org.curriki.gwt.server.CurrikiServiceImpl.getCompositeAsset(CurrikiServiceImpl.java:1560) at sun.reflect.GeneratedMethodAccessor894.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:528) at com.google.gwt.user.server.rpc.RemoteServiceServlet.processCall(RemoteServiceServlet.java:265) at com.xpn.xwiki.gwt.api.server.XWikiServiceImpl.processCall(XWikiServiceImpl.java:85) at com.google.gwt.user.server.rpc.RemoteServiceServlet.doPost(RemoteServiceServlet.java:187) at javax.servlet.http.HttpServlet.service(HttpServlet.java:727) at javax.servlet.http.HttpServlet.service(HttpServlet.java:820) at org.apache.catalina.core.ApplicationFilterChain.servletService(ApplicationFilterChain.java:397) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:184) at com.xpn.xwiki.web.SavedRequestRestorerFilter.doFilter(SavedRequestRestorerFilter.java:287) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:216) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:184) at com.xpn.xwiki.web.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:112) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:216) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:184) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:276) at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:566) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:536) at org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:240) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:179) at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:566) at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:73) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:182) at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:566) at com.sun.enterprise.web.VirtualServerPipeline.invoke(VirtualServerPipeline.java:120) at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:939) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:137) at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:566) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:536) at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:939) at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:239) at com.sun.enterprise.web.connector.grizzly.ProcessorTask.invokeAdapter(ProcessorTask.java:667) at com.sun.enterprise.web.connector.grizzly.ProcessorTask.processNonBlocked(ProcessorTask.java:574) at com.sun.enterprise.web.connector.grizzly.ProcessorTask.process(ProcessorTask.java:844) at com.sun.enterprise.web.connector.grizzly.ReadTask.executeProcessorTask(ReadTask.java:287) at com.sun.enterprise.web.connector.grizzly.ReadTask.doTask(ReadTask.java:212) at com.sun.enterprise.web.connector.grizzly.TaskBase.run(TaskBase.java:252) at com.sun.enterprise.web.connector.grizzly.WorkerThread.run(WorkerThread.java:75) Wrapped Exception: java.lang.NullPointerException