Enable/Disable windows users

In Sharing/FileSharing, Options, the users that already existed in 10.6 (before the upgrade) can't be disabled the windows sharing, when trying to do that, it ask for the password and after writing it correctly, nothing happens, the new users can be enabled and disabled without any problem, but not the old ones.

Is there any file with that config, that an be erased ?

It looks like its a bug in the system for users upgrading from snow, but no one report how to fix this