Subreport Problem with C#

I've got a relatively simple desktop application written in C# VS2005. I'm trying to get a report with a summarizing SubReport to display. The report displays fine without the SubReport and the SubReport displays okay as a stand alone, but I continue to crash with an "object not set to an instance..." error message. It must be that I'm not configuring the SubReport within the main report correct. I'm displaying the report using the CrystalReportViewer. Any help or sample code would be greatly appreciated.

TIA

Brad