Fixed NPE in AbstractEmfModel
diff --git a/plugins/org.eclipse.epsilon.emc.emf/src/org/eclipse/epsilon/emc/emf/AbstractEmfModel.java b/plugins/org.eclipse.epsilon.emc.emf/src/org/eclipse/epsilon/emc/emf/AbstractEmfModel.java
index 2fce44d..86668ec 100644
--- a/plugins/org.eclipse.epsilon.emc.emf/src/org/eclipse/epsilon/emc/emf/AbstractEmfModel.java
+++ b/plugins/org.eclipse.epsilon.emc.emf/src/org/eclipse/epsilon/emc/emf/AbstractEmfModel.java
@@ -377,8 +377,13 @@
 		registry = null;

 		if (modelImpl != null) {

 			Cache cache = CachedResourceSet.getCache();

-			for (Resource r : modelImpl.getResourceSet().getResources()) {

-				cache.returnResource(r);

+			if (modelImpl.getResourceSet() != null) {

+				for (Resource r : modelImpl.getResourceSet().getResources()) {

+					cache.returnResource(r);

+				}

+			}

+			else {

+				cache.returnResource(modelImpl);

 			}

 			modelImpl = null;

 		}