Database schema change

Crystal is usually good with handling database schema changes, but it has limitations. If you change underlaying schema substantially, for instance, remove parameters, or change cursor, you can get that awfull 'Illegal operation' error, while Crystal Reports shuts itself down.
To avoid that, if you know that database changed substantially, don't even attempt to do "Verify database", but go and update database location to that same table/stored procedure/package that you had before. Crystal will rewrite new schema without attempting to verify old one, and then you can proceed to reconcile your report with new changes.