Invalid Argument provided

Error message I get is:
"Invalid Argument provided Details: Object reference not set to an instance of an object."

I get this message every time I run the report. If I verify database before runing report, message is gone and report runs fine. Data connection is done using a VB file datasets (DLL). There are few subreports on this file which use same DLL but different datasets. If reports are removed report runs fine no error messages.

Any ideas would be much appreciated.

RobertFound the issue, one of Crystal dll was not properly registered (by install), once you re-install everything works fine.

Cheers|||Found the issue, one of Crystal dll was not properly registered (by install), once you re-install everything works fine.

Cheers
It is appreciable that you shared the solution :)