During export to PDF, I received the following error:

at ssUltimatePDF.Actions.ActionPrintToPDF_Advanced(HeContext heContext, String inParamURL, String inParamPaperSize, String inParamMarginSize, Byte[]& outParamPDF)
at ssUltimatePDF.Actions.ActionPrintToPDF(HeContext heContext, String inParamURL, Byte[]& outParamPDF)
at ssUltimatePDF.Flows.FlowPrintLayout.WBlkScreenToPDF.Preparation(HeContext heContext)
at ssUltimatePDF.Flows.FlowPrintLayout.WBlkScreenToPDF.Page_Load(Object sender, EventArgs e)
at ssUltimatePDF.Flows.FlowPrintLayout.WBlkScreenToPDF.PageStartHook()
at ASP.blocks_ultimatepdf_printlayout_screentopdf_ascx.__DataBind__control2(Object sender, EventArgs e)
at System.Web.UI.Control.OnDataBinding(EventArgs e)
at System.Web.UI.Control.DataBind(Boolean raiseOnDataBinding)
at OutSystems.HubEdition.WebWidgets.OSUserControl.DataBindChildren()
at System.Web.UI.Control.DataBind(Boolean raiseOnDataBinding)
at OutSystems.HubEdition.WebWidgets.OSUserControl.DataBind()
at OutSystems.HubEdition.WebWidgets.Form.DataBindChildren()
at System.Web.UI.Control.DataBind(Boolean raiseOnDataBinding)
at OutSystems.HubEdition.WebWidgets.Body.DataBindChildren()
at System.Web.UI.Control.DataBind(Boolean raiseOnDataBinding)
at OutSystems.HubEdition.WebWidgets.OSPage.DataBindChildren()
at System.Web.UI.Control.DataBind(Boolean raiseOnDataBinding)
at OutSystems.HubEdition.WebWidgets.OSPage.DataBind()
at ssartemispdf.Flows.FlowMainFlow.ScrnPDFReport.DataBind()
at ssartemispdf.Flows.FlowMainFlow.ScrnPDFReport.Page_Load(Object sender, EventArgs e)
at System.Web.UI.Control.OnLoad(EventArgs e)
at System.Web.UI.Control.LoadRecursive()
   at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)