The Microsoft Jet database engine cannot find the input table or query 'FORUM_ACTIVE_USERS'. Make sure it exists and that its name is spelled correctly.
If you have the dbs for the active users mod, execute it from mod setup. If you are unable to do it, backup the files who cause the error, replace them by base version files and run mod setup. After running the active users dbs file, restore the backed up files.
What setup? You mean the mod setup? If the dbs file was run and you had no error messages, it would not be possible for the same error to occur elsewhere... Are you sure it is the same error?