Issues while generating pdf output using Connected query

i have written an app engine program to pass run control parameters to the Connected Query.

The program then generates pdf output when the data source is Connected Query.

however processreport is erroring out. Any help will be appreciated.

Code:

&reportDefnObject.ProcessReport("tmplateid", "ENG", %Date, "PDF");

error:

	Error occurred while processing the request. (228,101) PT_CONQRS.CONQRSMGR.OnExecute  Name:GetXMLDat a  PCPC:53952  Statement:1203 Called from:PT_CONQRS.CONQRSMGR.OnExecute  Name:Run  Statement:453 Called from:PSXP_RPTDEFNMANAGER.ReportDefn.OnExecute  Name:GenerateXmlFileFromConnQuery  Statement:1 844 Called from:PSXP_RPTDEFNMANAGER.ReportDefn.OnExecute  Name:ProcessReport