The report engine looks at the default printer of your client browser environment or the default printer that is set for the ASP.NET Account, which is usually, is nothing if this is a web environment. You can set the printer’s name to a null string (“”) to tell ActiveReports to not look for a printer and it will figure out proper page settings on its own.

protected void WebGrid1_PrepareExportExecute(object sender, ISNet.WebUI.WebGrid.PrepareExportExecuteEventArgs e)
{
    e.ReportObject.Document.Printer.PrinterName = "";
}

Hope this helps.

because of the access right to folder~but thank you all the same~