Data retrieval failed for the subreport in RDLC Reporting

The code for sub report -

void SubReportQuestionHeadProcessing(object sender, SubreportProcessingEventArgs e)

{

switch (e.ReportPath)

{

case "SubRptQuestionHeads":

{

DataTable ldtQA = new DataTable();

int MonitoringDataID = Convert.ToInt32(e.Parameters["MonitoringDataID"].Values[0]);

int OrganizationId = Convert.ToInt32(e.Parameters["OrganizationId"].Values[0]);

int TemplateId = Convert.ToInt32(e.Parameters["TemplateId"].Values[0]);

int HeadID = Convert.ToInt32(e.Parameters["HeadID"].Values[0]);

String RowNumber = Convert.ToString(e.Parameters["RowNumber"].Values[0]);

ldtQA = Anidan.BLL.MonitoringData.GetMonitoringReportDataQuestionAnswersForMAStudy(MonitoringDataID, OrganizationId, TemplateId, HeadID, RowNumber);

e.DataSources.Add(new ReportDataSource("DS_QuestionAnswers", ldtQA));

break;

}

}

}