'Class not registered' error, Urgent!!!

I am pretty deperate. I have developed a database application in VB6. It is running just fine on my machine, but the program installed by the Setup Package generated with the Package and Deployment Wizard won't run on any other machine. Trying to connect to the database, it gives the error message "Run-time error '-2147221164 (80040154)': Class not registered". I tracked the problem down to the code line opening the database. It is DataEnv.DB.Open "Provider=MSDataShape;Persist Security Info=False;Data Source=" & FileTempDB & ";Mode=Share Deny None;Data Provider=Microsoft.Jet.OLEDB.3.51". I guess the problem has to do with the dataenvironment or the jet database engine, but I could not get around it. The database I open is a Access 97 file.
If any one has an answer, please let me know.
Thanks.

I have already solved the problem: Switching to Jet 4 has done the trick. And I better don't ask for the reason...

Thanks.