An error occurred in linking to User Database : Unknown function

[John and Therese Schilt]

Scenario : Access 2000 , application split with data in backend .mdb and
application in front end .mdb. Rolled out to our users with run-time licence

Issue : user gets the following error message :

An error occurred in linking to User Database : Unknown function

This user also has Office 2003 (with Access 2003).

Has anybody come across this error message ?

Thanks

John and Therese Schilt