--- SessionDynamicStore.bak	Tue Dec 18 15:45:39 2001
+++ SessionDynamicStore.py	Tue Oct 29 16:58:38 2002
@@ -143,7 +143,8 @@
 			global debug
 			if debug: print ">> Moving %s to File" % key
 			self._fileStore[key] = self._memoryStore[key]
-			del self._memoryStore[key]
+			if self._fileStore.has_key(key):	#delete session if only it stored ok
+				del self._memoryStore[key]
 		finally:
 			self._lock.release()