diff --git a/plugins/org.eclipse.m2m.qvt.oml.common/src/org/eclipse/m2m/internal/qvt/oml/common/resourcesetprovider/ResourceSetProviderRegistry.java b/plugins/org.eclipse.m2m.qvt.oml.common/src/org/eclipse/m2m/internal/qvt/oml/common/resourcesetprovider/ResourceSetProviderRegistry.java
index 0f60efa..6aa4b24 100644
--- a/plugins/org.eclipse.m2m.qvt.oml.common/src/org/eclipse/m2m/internal/qvt/oml/common/resourcesetprovider/ResourceSetProviderRegistry.java
+++ b/plugins/org.eclipse.m2m.qvt.oml.common/src/org/eclipse/m2m/internal/qvt/oml/common/resourcesetprovider/ResourceSetProviderRegistry.java
@@ -62,7 +62,9 @@
     static {
         refresh();
         Platform.getExtensionRegistry().addRegistryChangeListener(ourRegistryChangeListener, CommonPlugin.ID);
-        PlatformUI.getWorkbench().getActivitySupport().getActivityManager().addActivityManagerListener(ourActivityChangeListener);
+        if(PlatformUI.isWorkbenchRunning()) {
+        	PlatformUI.getWorkbench().getActivitySupport().getActivityManager().addActivityManagerListener(ourActivityChangeListener);
+        }
     }
     
     public static final ResourceSetResourceSetProviderPair getResourceSetResourceSetProviderPair(CFile script) {