fixing junit test exceptions
diff --git a/update/org.eclipse.update.core/src/org/eclipse/update/core/Utilities.java b/update/org.eclipse.update.core/src/org/eclipse/update/core/Utilities.java
index 0649c4a..f35f255 100644
--- a/update/org.eclipse.update.core/src/org/eclipse/update/core/Utilities.java
+++ b/update/org.eclipse.update.core/src/org/eclipse/update/core/Utilities.java
@@ -226,7 +226,8 @@
 		} else {
 			ce.initCause(e);
 		}
-		e.setStackTrace(e.getStackTrace());
+		if (e != null)
+			ce.setStackTrace(e.getStackTrace());
 		return ce; 
 	}