Does the report run correctly from Crystal? From this message, I can see that the report is using a stored procedure to get to it's data. In some databases, you can set up stored procedures so that you can pass null values to the parameters. However, Crystal requires that you set SOME value to each of the parameters of a stored procedure.
So, this error is telling me one of a couple of things is going on:
1. Your code is trying to modify a report to make a stored procedure parameter nullable. Crystal will not let you do this with stored procedure variables.
2. You're trying to run a report without setting values for all of the parameters.
Without seeing the code you're using to run the report, I can't tell for sure which issue is causing the problem.
-Dell