NPE when trying to save file in Eclipse Drools Editor

eclipse.buildId=M20071023-1652
java.version=1.5.0_13
java.vendor=Apple Computer, Inc.
BootLoader constants: OS=macosx, ARCH=x86, WS=carbon, NL=en_US
Framework arguments: -keyring /Users/marcus/.eclipse_keyring -showlocation
Command-line arguments: -os macosx -ws carbon -arch x86 -keyring /Users/marcus/.eclipse_keyring -consoleLog -showlocation

Warning
Sun Jan 13 22:40:39 CET 2008
Save Failed

java.lang.NullPointerException
at org.drools.eclipse.util.ProjectClassLoader.getRawLocationFile(Unknown Source)
at org.drools.eclipse.util.ProjectClassLoader.getRawLocationURL(Unknown Source)
at org.drools.eclipse.util.ProjectClassLoader.getProjectClassPathURLs(Unknown Source)
at org.drools.eclipse.util.ProjectClassLoader.getProjectClassPathURLs(Unknown Source)
at org.drools.eclipse.util.ProjectClassLoader.getProjectClassLoader(Unknown Source)
at org.drools.eclipse.DroolsEclipsePlugin.generateParsedResource(Unknown Source)
at org.drools.eclipse.DroolsEclipsePlugin.parseResource(Unknown Source)
at org.drools.eclipse.editors.outline.RuleContentOutlinePage.initRules(Unknown Source)
at org.drools.eclipse.editors.outline.RuleContentOutlinePage.update(Unknown Source)
at org.drools.eclipse.editors.AbstractRuleEditor.doSave(Unknown Source)
at org.drools.eclipse.editors.DRLRuleEditor.doSave(Unknown Source)
at org.drools.eclipse.editors.DRLRuleEditor2.doSave(Unknown Source)
at org.eclipse.ui.internal.SaveableHelper$1.run(SaveableHelper.java:143)
at org.eclipse.ui.internal.SaveableHelper$4.run(SaveableHelper.java:266)
at org.eclipse.jface.operation.ModalContext.runInCurrentThread(ModalContext.java:369)
at org.eclipse.jface.operation.ModalContext.run(ModalContext.java:313)
at org.eclipse.jface.window.ApplicationWindow$1.run(ApplicationWindow.java:758)
at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:67)
at org.eclipse.jface.window.ApplicationWindow.run(ApplicationWindow.java:755)
at org.eclipse.ui.internal.WorkbenchWindow.run(WorkbenchWindow.java:2451)
at org.eclipse.ui.internal.SaveableHelper.runProgressMonitorOperation(SaveableHelper.java:274)
at org.eclipse.ui.internal.SaveableHelper.runProgressMonitorOperation(SaveableHelper.java:253)
at org.eclipse.ui.internal.SaveableHelper.savePart(SaveableHelper.java:148)
at org.eclipse.ui.internal.EditorManager.savePart(EditorManager.java:1345)
at org.eclipse.ui.internal.WorkbenchPage.savePart(WorkbenchPage.java:3202)
at org.eclipse.ui.internal.WorkbenchPage.saveEditor(WorkbenchPage.java:3215)
at org.eclipse.ui.internal.SaveAction.run(SaveAction.java:73)
at org.eclipse.jface.action.Action.runWithEvent(Action.java:498)
at org.eclipse.jface.commands.ActionHandler.execute(ActionHandler.java:119)
at org.eclipse.core.commands.Command.executeWithChecks(Command.java:475)
at org.eclipse.core.commands.ParameterizedCommand.executeWithChecks(ParameterizedCommand.java:429)
at org.eclipse.ui.internal.handlers.HandlerService.executeCommand(HandlerService.java:165)
at org.eclipse.ui.internal.keys.WorkbenchKeyboard.executeCommand(WorkbenchKeyboard.java:470)
at org.eclipse.ui.internal.keys.WorkbenchKeyboard.press(WorkbenchKeyboard.java:821)
at org.eclipse.ui.internal.keys.WorkbenchKeyboard.processKeyEvent(WorkbenchKeyboard.java:879)
at org.eclipse.ui.internal.keys.WorkbenchKeyboard.filterKeySequenceBindings(WorkbenchKeyboard.java:568)
at org.eclipse.ui.internal.keys.WorkbenchKeyboard.access$3(WorkbenchKeyboard.java:510)
at org.eclipse.ui.internal.keys.WorkbenchKeyboard$KeyDownFilter.handleEvent(WorkbenchKeyboard.java:126)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:66)
at org.eclipse.swt.widgets.Display.filterEvent(Display.java:1101)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1494)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1519)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1504)
at org.eclipse.swt.widgets.Widget.sendKeyEvent(Widget.java:1556)
at org.eclipse.swt.widgets.Widget.sendKeyEvent(Widget.java:1551)
at org.eclipse.swt.widgets.Control.kEventUnicodeKeyPressed(Control.java:2090)
at org.eclipse.swt.widgets.Composite.kEventUnicodeKeyPressed(Composite.java:580)
at org.eclipse.swt.widgets.Control.kEventTextInputUnicodeForKeyEvent(Control.java:2071)
at org.eclipse.swt.widgets.Widget.textInputProc(Widget.java:1925)
at org.eclipse.swt.widgets.Display.textInputProc(Display.java:3806)
at org.eclipse.swt.internal.carbon.OS.SendEventToEventTarget(Native Method)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:2938)
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(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:508)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:447)
at org.eclipse.equinox.launcher.Main.run(Main.java:1173)