Access Bound Forms and ODBC-Driver

Hello, 

in Access 97 I have bound forms. I have linked my sapdb tables manually and
via VBA into Access. If I open such a bound form the dialog-box from the
ODBC-Driver opens and asks for a valid login. Sometimes I'm getting asked a
lot of times. And even if I type a valid login the form doesn't work like
under a pure Access-Environment. 
How can I get rid of this dialog-box? Maybe then my forms will work again.

Thanks in advance
Peter Huebschen