I would think that the user's should have the same odbc as your tables are linked to ... Have you tried a 'pass-thru' query called from an 'AUTOEXEC' macro at the very beginning (to get around the user/password) ??
Pass-thru query is setup as a special query in which you go directly to the database ... in properties of the design you give the username, password and database ... It doesn't look at any other object in Access, but directly at the database you have given in the pass-thru query... If you have a macro defined as AUTOEXEC, upon starting Access, it will execute whatever you have defined in autoexec first... I setup a pass-thru query to "select x from a database_table".. I then setup an AUTOEXEC macro to call that query... That way I ensure a database connection prior to running an app..