Index: mozilla/mailnews/news/src/nsNNTPNewsgroupList.cpp
===================================================================
RCS file: /cvsroot/mozilla/mailnews/news/src/nsNNTPNewsgroupList.cpp,v
retrieving revision 1.140
diff -u -p -r1.140 nsNNTPNewsgroupList.cpp
--- mozilla/mailnews/news/src/nsNNTPNewsgroupList.cpp	30 Apr 2008 01:35:21 -0000	1.140
+++ mozilla/mailnews/news/src/nsNNTPNewsgroupList.cpp	7 May 2008 07:41:12 -0000
@@ -790,11 +790,13 @@ NS_IMETHODIMP nsNNTPNewsgroupList::Apply
         break;
       case nsMsgFilterAction::KillThread:
         {
-          PRUint32 newFlags;
           nsCOMPtr<nsIMsgThread> thread;
-          m_newsDB->GetThreadContainingMsgHdr(m_newMsgHdr, getter_AddRefs(thread) );
-          thread->GetFlags(&newFlags);
-          thread->SetFlags(newFlags | MSG_FLAG_IGNORED);
+          rv = m_newsDB->GetThreadContainingMsgHdr(m_newMsgHdr, getter_AddRefs(thread) );
+          if (NS_SUCCEEDED(rv)) {
+            PRUint32 newFlags;
+            thread->GetFlags(&newFlags);
+            thread->SetFlags(newFlags | MSG_FLAG_IGNORED);
+          }
         }
         break;
       case nsMsgFilterAction::KillSubthread: