Exporting Crystal Report to PDF throws error: Error detected by export DLL: (541)

This is a common problem with embedding Crystal Reports in ASP pages. Essentially, the authentication details are reset on a postback and need to be reassigned in the Page_Init handler. This article provides code examples and a link to MSDN explaining the ConnectionInfo class and how it works in this context. In case that link dies, the solution is in two steps:

First, import these:

Imports CrystalDecisions.Shared
Imports CrystalDecisions.CrystalReports.Engine

Then, in the Page_Init handler, re-apply connection info:

Dim myConnectionInfo As ConnectionInfo = New ConnectionInfo()
Dim myReport As New ReportDocument()
myReport.Load(Server.MapPath("ReportName")) -- name of the crystal report

Dim myTables As Tables = myReport.Database.Tables

For Each myTable As CrystalDecisions.CrystalReports.Engine.Table In myTables
  Dim myTableLogonInfo As TableLogOnInfo = myTable.LogOnInfo
  myConnectionInfo.ServerName = "" -- <SQL servername>
  myConnectionInfo.DatabaseName = "" -- leave database name blank
  myConnectionInfo.UserID = "" -- username
  myConnectionInfo.Password = "" -- password
  myTableLogonInfo.ConnectionInfo = myConnectionInfo
  myTable.ApplyLogOnInfo(myTableLogonInfo)
Next

CrystalReportViewer1.ReportSource = myReport

Note - SO doesn't like VB comments and wants to call them (and subsequent lines) literal strings instead. Used C/Java comment operator instead.

Try This:

private void MenuItemPrint()
{
   if (!FileName.Trim().Equals(""))
   {                        
     using(PrintDocument pd = new PrintDocument())
     {
        using(PrintDialog printDialog=new PrintDialog())
        {
          if(printDialog.ShowDialog()==DialogResult.Yes)
          {
          pd.PrintPage += new PrintPageEventHandler(pd_PrintPage);                        
          pd.Print();
          }
         }
      }
    }
 }
private void pd_PrintPage(object sender, PrintPageEventArgs ev)
{
  ev.Graphics.DrawString(FileName, new Font("Arial", 10), Brushes.Black,
                       ev.MarginBounds.Left, 0, new StringFormat());
 }