jsp open error

java.lang.IllegalArgumentException: Argument not valid
at org.eclipse.swt.SWT.error(SWT.java:3547)
at org.eclipse.swt.SWT.error(SWT.java:3481)
at org.eclipse.swt.SWT.error(SWT.java:3452)
at org.eclipse.swt.custom.SashForm.setWeights(SashForm.java:374)
at com.genuitec.eclipse.webdesigner3.editors.WebDesignerMultiPageEditor.configureSash(WebDesignerMultiPageEditor.java:637)
at com.genuitec.eclipse.webdesigner3.editors.WebDesignerMultiPageEditor.createDesignPage(WebDesignerMultiPageEditor.java:573)
at com.genuitec.eclipse.webdesigner3.editors.WebDesignerMultiPageEditor.createPages(WebDesignerMultiPageEditor.java:340)
at org.eclipse.ui.part.MultiPageEditorPart.createPartControl(MultiPageEditorPart.java:283)
at org.eclipse.ui.internal.EditorReference.createPartHelper(EditorReference.java:661)
at org.eclipse.ui.internal.EditorReference.createPart(EditorReference.java:426)
at org.eclipse.ui.internal.WorkbenchPartReference.getPart(WorkbenchPartReference.java:592)
at org.eclipse.ui.internal.EditorReference.getEditor(EditorReference.java:263)
at org.eclipse.ui.internal.WorkbenchPage.busyOpenEditorBatched(WorkbenchPage.java:2739)
at org.eclipse.ui.internal.WorkbenchPage.busyOpenEditor(WorkbenchPage.java:2651)
at org.eclipse.ui.internal.WorkbenchPage.access$13(WorkbenchPage.java:2643)
at org.eclipse.ui.internal.WorkbenchPage$10.run(WorkbenchPage.java:2595)
at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:67)
at org.eclipse.ui.internal.WorkbenchPage.openEditor(WorkbenchPage.java:2590)
at org.eclipse.ui.internal.WorkbenchPage.openEditor(WorkbenchPage.java:2574)
at org.eclipse.ui.internal.WorkbenchPage.openEditor(WorkbenchPage.java:2565)
at org.eclipse.ui.ide.IDE.openEditor(IDE.java:644)
at org.eclipse.ui.ide.IDE.openEditor(IDE.java:603)
at org.eclipse.ui.actions.OpenFileAction.openFile(OpenFileAction.java:98)
at org.eclipse.ui.actions.OpenSystemEditorAction.run(OpenSystemEditorAction.java:98)
at org.eclipse.ui.views.navigator.OpenActionGroup.runDefaultAction(OpenActionGroup.java:125)
at org.eclipse.ui.views.navigator.MainActionGroup.runDefaultAction(MainActionGroup.java:328)
at org.eclipse.ui.views.navigator.ResourceNavigator.handleOpen(ResourceNavigator.java:690)
at org.eclipse.ui.views.navigator.ResourceNavigator$6.open(ResourceNavigator.java:433)
at org.eclipse.jface.viewers.StructuredViewer$2.run(StructuredViewer.java:820)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:37)
at org.eclipse.core.runtime.Platform.run(Platform.java:857)
at org.eclipse.ui.internal.JFaceUtil$1.run(JFaceUtil.java:46)
at org.eclipse.jface.util.SafeRunnable.run(SafeRunnable.java:199)
at org.eclipse.jface.viewers.StructuredViewer.fireOpen(StructuredViewer.java:818)
at org.eclipse.jface.viewers.StructuredViewer.handleOpen(StructuredViewer.java:1079)
at org.eclipse.jface.viewers.StructuredViewer$6.handleOpen(StructuredViewer.java:1183)
at org.eclipse.jface.util.OpenStrategy.fireOpenEvent(OpenStrategy.java:263)
at org.eclipse.jface.util.OpenStrategy.access$2(OpenStrategy.java:257)
at org.eclipse.jface.util.OpenStrategy$1.handleEvent(OpenStrategy.java:297)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:66)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:938)
at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:3682)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3293)
at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:2389)
at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2353)
at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2219)
at org.eclipse.ui.internal.Workbench$4.run(Workbench.java:466)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:289)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:461)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:106)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:169)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:106)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:76)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:363)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:176)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:508)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:447)
at org.eclipse.equinox.launcher.Main.run(Main.java:1173)
at org.eclipse.equinox.launcher.Main.main(Main.java:1148)