Stored procedures in Crystal are very picky - even more so it the schema owners or database name change.
How are you migrating the reports to UAT? Are they a copy of the report from your Dev environment and the code handles changing the connection? If so, you may want to open the rpt file from UAT and use Set Location to point the report to the UAT database (and eventually to the Prod database when you move it there.) It can be a big hassle, but if that's what it takes to get it to work, then it will be worth it.
-Dell