The two databases use different drivers - the older driver in the report won't work with the new database.  With your version of Crystal (>10 years old), you probably won't be able to connect it to the new database.  To try, open the report in the designer but DO NOT RUN!.  Try to connect to your converted database.  If the connection doesn't work, you won't be able to do anything with the new db unless you upgrade your Crystal.

Are you running it from inside Crystal or through another application?  If it's through another application, does that run on a different server under a different login?  If so, does that user ID have access to the folder where the new database resides?