eventhough I have passed value in .NET code, getting parameter panel

Hi,

I am developing crystal report 2008 with C# .NET 2010.

Environment:

OS : Windows 7

Report designed in CR2008

.NET Framework 4 (VS2010)

Running in CR for VS2010 (13_0_2)

I am passing a value to the report paramter filed through .NET code. (i.e. Name of the user who logged into the application - This I created a report parameter field in the report and pass value to it from .NET code using rpt.setParameterValue("UserName", "Mani") ) . What happens is When I run the application sometimes unpredictably I am getting parameter panel prompting for value eventhough I have passed value to it in the code. Do not know why?

How to resolve it?

Please help me Sir.

Regards,

Mani g.s.