error database table doesn't exist

Does it work with table prefixes ?
becase I get this error when I press grant tab...

I replaced "databasename" and "prefix" in this:

user warning: Table 'databasename.users' doesn't exist query: SELECT uid, name FROM prefix_node_access na LEFT JOIN users ON uid=gid WHERE nid=12 AND realm='nodeaccess_uid' in /mysite/includes/database.mysql.inc on line 120.

I think it should look in databasename."prefix"users