NullPointerException occures when using CA

When using CA on XHTML:

java.lang.NullPointerException
at org.jboss.tools.jst.web.kb.internal.taglib.AbstractTagLib.getComponents(AbstractTagLib.java:109)
at org.jboss.tools.jst.web.kb.internal.taglib.AbstractTagLib.getComponents(AbstractTagLib.java:247)
at org.jboss.tools.jst.web.kb.internal.taglib.AbstractTagLib.getComponentsByPrefixes(AbstractTagLib.java:188)
at org.jboss.tools.jst.web.kb.internal.taglib.AbstractTagLib.getProposals(AbstractTagLib.java:414)
at org.jboss.tools.jst.web.kb.PageProcessor.getProposals(PageProcessor.java:67)
at org.jboss.tools.jst.jsp.contentassist.XmlContentAssistProcessor.addTagNameProposalsForPrefix(XmlContentAssistProcessor.java:125)
at org.jboss.tools.jst.jsp.contentassist.XmlContentAssistProcessor.addTagNameProposals(XmlContentAssistProcessor.java:217)
at org.jboss.tools.jst.jsp.contentassist.XmlContentAssistProcessor.addTagNameProposals(XmlContentAssistProcessor.java:179)
at org.jboss.tools.jst.jsp.contentassist.AbstractXMLContentAssistProcessor.computeTagNameProposals(AbstractXMLContentAssistProcessor.java:229)
at org.eclipse.wst.xml.ui.internal.contentassist.AbstractContentAssistProcessor.computeCompletionProposals(AbstractContentAssistProcessor.java:1282)
at org.jboss.tools.jst.jsp.contentassist.AbstractXMLContentAssistProcessor.computeCompletionProposals(AbstractXMLContentAssistProcessor.java:541)
at org.eclipse.wst.xml.ui.internal.contentassist.AbstractContentAssistProcessor.computeCompletionProposals(AbstractContentAssistProcessor.java:1407)
at org.jboss.tools.jst.jsp.contentassist.AbstractXMLContentAssistProcessor.computeCompletionProposals(AbstractXMLContentAssistProcessor.java:91)
at org.jboss.tools.common.text.xml.contentassist.SortingCompoundContentAssistProcessor.computeCompletionProposals(SortingCompoundContentAssistProcessor.java:234)
at org.eclipse.wst.sse.ui.internal.contentassist.CompoundContentAssistProcessor.computeCompletionProposals(CompoundContentAssistProcessor.java:303)
at org.eclipse.jface.text.contentassist.ContentAssistant.computeCompletionProposals(ContentAssistant.java:1832)
at org.eclipse.jface.text.contentassist.CompletionProposalPopup.computeProposals(CompletionProposalPopup.java:556)
at org.eclipse.jface.text.contentassist.CompletionProposalPopup.access$16(CompletionProposalPopup.java:553)
at org.eclipse.jface.text.contentassist.CompletionProposalPopup$2.run(CompletionProposalPopup.java:488)
at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:70)
at org.eclipse.jface.text.contentassist.CompletionProposalPopup.showProposals(CompletionProposalPopup.java:482)
at org.eclipse.jface.text.contentassist.ContentAssistant.showPossibleCompletions(ContentAssistant.java:1660)
at org.eclipse.wst.sse.ui.internal.StructuredTextViewer.doOperation(StructuredTextViewer.java:446)
at org.jboss.tools.jst.jsp.jspeditor.JSPTextEditor$JSPStructuredTextViewer.doOperation(JSPTextEditor.java:678)
at org.eclipse.ui.texteditor.TextOperationAction$1.run(TextOperationAction.java:131)
at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:70)
at org.eclipse.ui.texteditor.TextOperationAction.run(TextOperationAction.java:129)
at org.eclipse.jface.action.Action.runWithEvent(Action.java:498)
at org.eclipse.ui.commands.ActionHandler.execute(ActionHandler.java:185)
at org.eclipse.ui.internal.handlers.LegacyHandlerWrapper.execute(LegacyHandlerWrapper.java:109)
at org.eclipse.core.commands.Command.executeWithChecks(Command.java:476)
at org.eclipse.core.commands.ParameterizedCommand.executeWithChecks(ParameterizedCommand.java:508)
at org.eclipse.ui.internal.handlers.HandlerService.executeCommand(HandlerService.java:169)
at org.eclipse.ui.internal.keys.WorkbenchKeyboard.executeCommand(WorkbenchKeyboard.java:470)
at org.eclipse.ui.internal.keys.WorkbenchKeyboard.press(WorkbenchKeyboard.java:824)
at org.eclipse.ui.internal.keys.WorkbenchKeyboard.processKeyEvent(WorkbenchKeyboard.java:880)
at org.eclipse.ui.internal.keys.WorkbenchKeyboard.filterKeySequenceBindings(WorkbenchKeyboard.java:569)
at org.eclipse.ui.internal.keys.WorkbenchKeyboard.access$3(WorkbenchKeyboard.java:510)
at org.eclipse.ui.internal.keys.WorkbenchKeyboard$KeyDownFilter.handleEvent(WorkbenchKeyboard.java:125)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
at org.eclipse.swt.widgets.Display.filterEvent(Display.java:1191)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1002)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1027)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1012)
at org.eclipse.swt.widgets.Widget.sendKeyEvent(Widget.java:1040)
at org.eclipse.swt.widgets.Widget.sendKeyEvent(Widget.java:1036)
at org.eclipse.swt.widgets.Widget.wmChar(Widget.java:1368)
at org.eclipse.swt.widgets.Control.WM_CHAR(Control.java:4047)
at org.eclipse.swt.widgets.Canvas.WM_CHAR(Canvas.java:346)
at org.eclipse.swt.widgets.Control.windowProc(Control.java:3940)
at org.eclipse.swt.widgets.Canvas.windowProc(Canvas.java:342)
at org.eclipse.swt.widgets.Display.windowProc(Display.java:4589)
at org.eclipse.swt.internal.win32.OS.DispatchMessageW(Native Method)
at org.eclipse.swt.internal.win32.OS.DispatchMessage(OS.java:2409)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3471)
at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:2405)
at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2369)
at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2221)
at org.eclipse.ui.internal.Workbench$5.run(Workbench.java:500)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:493)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:113)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:194)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:368)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:179)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:559)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:514)
at org.eclipse.equinox.launcher.Main.run(Main.java:1311)
at org.eclipse.equinox.launcher.Main.main(Main.java:1287)