Can you pass name in first parameter which is not any control but a static name
if you want to pass any controls value please specify it.
string strUrl = "wbFrmReportViewer.aspx?RepName=ApprovalReportByDateTime&OptionStatus=" + ddlSelectReport.SelectedValue.Trim()+ "&Date=" + dptDate.Text.Trim() + "&Param=" + strParam;
Response.Redirect(strUrl);