How to link PART & PARTTRAN

Making a Crystal Report and when I link those two tables using the fields; COMPANY and PARTNUM i get an error message saying, "Failed to connect to the database.

I'm certain it is something with this link because I have tried other tables and reports and work just fine.

Does anyone have any suggestions of what links to use? I was suggested not to use SysRowID because it would duplicate each record?