VFP7 SP1 , Crystal Reports V8.5

I really need help with this, I cannot go any further.

I am in the process of testing the RDC / Report Viewer. In the Report Viewer I would like to put some code into the DrillOnGroup Event but every time I try and Drill into the Report VFP Crashes with the famous C00000000005 Error, even if there is only comments in the event it still crashes. If I take out the code in the DrillOnGroup everything is O.K again.