Getting error while opening .bpmn file from eclipse from Referenced Libraries.

[kevin79059]

Getting error while opening .bpmn file from eclipse from Referenced Libraries. if i open another file from source, then it is not giving below error. 

java.lang.NullPointerException
at org.eclipse.graphiti.ui.editor.DiagramEditor.getDiagramTypeProvider(DiagramEditor.java:743)
at org.activiti.designer.eclipse.editor.ActivitiDiagramEditor.dispose(ActivitiDiagramEditor.java:1089)
at org.eclipse.ui.internal.e4.compatibility.CompatibilityPart.handlePartInitException(CompatibilityPart.java:309)
at org.eclipse.ui.internal.e4.compatibility.CompatibilityPart.create(CompatibilityPart.java:347)
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.e4.core.internal.di.MethodRequestor.execute(MethodRequestor.java:58)
at org.eclipse.e4.core.internal.di.InjectorImpl.processAnnotated(InjectorImpl.java:1001)
at org.eclipse.e4.core.internal.di.InjectorImpl.processAnnotated(InjectorImpl.java:966)
at org.eclipse.e4.core.internal.di.InjectorImpl.internalInject(InjectorImpl.java:139)
at org.eclipse.e4.core.internal.di.InjectorImpl.internalMake(InjectorImpl.java:411)
at org.eclipse.e4.core.internal.di.InjectorImpl.make(InjectorImpl.java:333)
at org.eclipse.e4.core.contexts.ContextInjectionFactory.make(ContextInjectionFactory.java:202)
at org.eclipse.e4.ui.internal.workbench.ReflectionContributionFactory.createFromBundle(ReflectionContributionFactory.java:91)
at org.eclipse.e4.ui.internal.workbench.ReflectionContributionFactory.doCreate(ReflectionContributionFactory.java:60)
at org.eclipse.e4.ui.internal.workbench.ReflectionContributionFactory.create(ReflectionContributionFactory.java:42)
at org.eclipse.e4.ui.workbench.renderers.swt.ContributedPartRenderer.createWidget(ContributedPartRenderer.java:132)