JR Crystal Reports, Getting QE Error : Unable to find parameter ''{0}''

I am getting the Error

QE Error unable to locate the parameter ''''

Kindly help me in resolving this.

I am using Tomcat 6.0 Application server and Crystal Reports 11.

I am getting the reports in the PDF format(export) by setting the resultset fot stored procedures.

When there are more than one stored procedures defined in report this error is coming otherwise not.

Regards.

Kazim Raza.