Crystal Reports Help: Error thrown saying it needs a Number

Message

     Hello Folks,
I have a crystal report which is populated by a stored procedure and when i try to run the report Its throwing an error saying "Number is required" and its pointing to the formula below.
{?@Payer}={rptInvoiceAnalysisB;1.clientid} or {?@Payer}=-1

Here ?@payer is parameter coming from Stored prodcedure and {rptInvoiceAnalysisB;1.clientid} is the field which is a numeric and the parameter is a number.

I think its throwing error because of -1 but not sure.Any thoughts about this. 

Thanks a lot 

Edited by Nav522 - 06 Apr 2010 at 9:52am