Activiti eclipse3.6.2流程图不能新建的问题

Activiti5.7 + eclipse3.6.2安装画流程图插件后，新建一个 流程图，点击“finish”时总是抱错，意味着新建流程图失败。错误如下：

Unhandled event loop exception

java.lang.IllegalArgumentException: The 'no null' constraint is violated
at org.eclipse.emf.common.util.AbstractEList.validate(AbstractEList.java:101)
at org.eclipse.emf.common.util.BasicEList.addUnique(BasicEList.java:424)
at org.eclipse.emf.common.notify.impl.NotifyingListImpl.doAddUnique(NotifyingListImpl.java:331)
at org.eclipse.emf.common.notify.impl.NotifyingListImpl.addUnique(NotifyingListImpl.java:288)
at org.eclipse.emf.common.util.AbstractEList.add(AbstractEList.java:307)
at org.activiti.designer.eclipse.common.FileService$1.doExecute(FileService.java:66)
at org.eclipse.emf.transaction.RecordingCommand.execute(RecordingCommand.java:135)
at org.eclipse.emf.workspace.EMFCommandOperation.doExecute(EMFCommandOperation.java:119)
at org.eclipse.emf.workspace.AbstractEMFOperation.execute(AbstractEMFOperation.java:150)
at org.eclipse.core.commands.operations.DefaultOperationHistory.execute(DefaultOperationHistory.java:511)
at org.eclipse.emf.workspace.impl.WorkspaceCommandStackImpl.doExecute(WorkspaceCommandStackImpl.java:208)
at org.eclipse.emf.transaction.impl.AbstractTransactionalCommandStack.execute(AbstractTransactionalCommandStack.java:165)
at org.eclipse.graphiti.ui.internal.editor.GFWorkspaceCommandStackImpl.execute(GFWorkspaceCommandStackImpl.java:71)
at org.eclipse.graphiti.ui.internal.editor.GFWorkspaceCommandStackImpl.execute(GFWorkspaceCommandStackImpl.java:58)
at org.eclipse.emf.transaction.impl.AbstractTransactionalCommandStack.execute(AbstractTransactionalCommandStack.java:219)
at org.eclipse.graphiti.ui.internal.editor.GFWorkspaceCommandStackImpl.execute(GFWorkspaceCommandStackImpl.java:53)
at org.activiti.designer.eclipse.common.FileService.createEmfFileForDiagram(FileService.java:60)
at org.activiti.designer.eclipse.ui.wizard.diagram.CreateDefaultActivitiDiagramWizard.performFinish(CreateDefaultActivitiDiagramWizard.java:168)
at org.eclipse.jface.wizard.WizardDialog.finishPressed(WizardDialog.java:811)

其实，只要在 window-preferences-activiti-editor项，把“create default diagram content...” 勾选去掉，就可以了。
[转]http://forums.activiti.org/en/viewtopic.php?f=8&t=1798