.mdb synchronizing error keeps appearing

I recently move my user’s homme directories to a new Windows 2003 server. I have my documents being redirected for each user and have always had a policy to cache redirected folders. Now my users are getting sync errors with .mdb, .pst, and .dbg files. I know they are not to synchronize but I can not get the synchronization process to ignore or skip these files. I have added the extensions to the “files not chached” group policy but still no better results. Anyone have any ideas?