--- a/thirdparty/google_appengine/google/appengine/api/memcache/memcache_stub.py	Thu Feb 12 10:24:37 2009 +0000
+++ b/thirdparty/google_appengine/google/appengine/api/memcache/memcache_stub.py	Thu Feb 12 12:30:36 2009 +0000
@@ -223,9 +223,11 @@
 
     try:
       old_value = long(entry.value)
+      if old_value < 0:
+        raise ValueError
     except ValueError, e:
       logging.error('Increment/decrement failed: Could not interpret '
-                    'value for key = "%s" as an integer.', key)
+                    'value for key = "%s" as an unsigned integer.', key)
       return
 
     delta = request.delta()