Problem When Multiple Users Export To PDF Simultaneously

Question

I am hoping someone out there can help.  We have had no luck at all with Crystal Reports / SAP support for this issue.
We have a client/server aplication and have written a C# program to load a crystal report on the server, export it to PDF and then we send the PDF to the client. We are using Crystal Reports 2008 and have applied SP4.
The scenario is as follows:
Two users log into our application from different PC's.
User 1 prints a report with no issue.
User 2 prints a report 5 seconds later with no issue.
If User 1 prints a report and while that report is being exported to PDF, User 2 prints a report, the first will be successful and the second will fail.  If User 2 reprints the report after receiving a failure, the report prints successfully the second time (using the same temp report folders as the previous attempt). We have done a lot of tracing and have narrowed the problem down to the point in out C# program when the cryRpt.Export() routine is called.  It seems to be what is failing and doesn't seem to be able to run 2 exports simultaneously.
All exporting to PDF occurs on the application server and the processes run as "Administrator" so permissions should certainly not be a problem.  Each user is printing a different physical .rpt file and the data for each report is in a different physical directory.
Has anyone come across this before or have any suggestions?

Answer 1

We thought the same thing as you suggest and have already made that change without sucess.  Below is what the code looks like for our export routine.  Perhaps you can spot something we have not.  As mentioned before the export appears to be faulting at the statement "cryRpt.ExportToDisk(ExportFormatType.PortableDocFormat, pdfname);" in the below code.
The code is as follows:
        public void exportReport(string xmldir, string crname, string pdfname, string termid, bool debug)
            try
                if (debug)
                    dt = DateTime.Now;
                    tw.WriteLine(dt.ToString() + "-Start exportReport: " + crname);
                ReportDocument cryRpt;
                cryRpt = new ReportDocument();
                cryRpt.Load(crname, OpenReportMethod.OpenReportByTempCopy);
                if (debug)
                    tw.WriteLine("Done loading report: " + crname);
                int tmpct = 0;
                int tmpint = crname.IndexOf("
", tmpct);
                while (tmpint != -1)
                    tmpct = tmpint;
                    tmpint = crname.IndexOf("
", tmpct + 1);
                string ODBCReportFileName = crname.Substring(tmpct + 1, crname.Length - tmpct - 5);
                if (debug)
                    tw.WriteLine("ODBC Report Filename: " + ODBCReportFileName);
                Database crDatabase;
                Tables crTables;
                Table crTable;
                TableLogOnInfo crTableLogOnInfo;
                ConnectionInfo crConnectionInfo = new ConnectionInfo();
                //Setup the connection information structure to log on to the data source for the report.
                // If using ODBC, this should be the DSN. If using OLEDB, etc, this should be the physical server name
                crConnectionInfo.ServerName = "SH" + ODBCReportFileName;
                if (debug)
                    tw.WriteLine("Resetting connection to: " + crConnectionInfo.ServerName);
                crConnectionInfo.DatabaseName = "";
                //Get the table information from the report
                crDatabase = cryRpt.Database;
                crTables = crDatabase.Tables;
                //Loop through all tables in the report and apply the
                //connection information for each table.
                if (debug)
                    tw.WriteLine("Applying new connection to all tables...");
                for (int i = 0; i < crTables.Count; i++)
                    crTable = crTables<i>;
                    crTableLogOnInfo = crTable.LogOnInfo;
                    crTableLogOnInfo.ConnectionInfo =
                    crConnectionInfo;
                    crTable.ApplyLogOnInfo(crTableLogOnInfo);
                    if (debug)
                        tw.WriteLine("Applying new connection to tables " + crTable.Name);
                cryRpt.Refresh();
                if (debug)
                    tw.WriteLine("Applying new connection to all tables... DONE");
                if (debug)
                    tw.WriteLine("Target report: " + pdfname);
                cryRpt.ExportToDisk(ExportFormatType.PortableDocFormat, pdfname);
                if (debug)
                    tw.WriteLine("Export Complete");
                cryRpt.Dispose();
                cryRpt.Close();
                if (debug)
                    dt = DateTime.Now;
                    tw.WriteLine(dt.ToString() + "-Done export to PDF.");
            catch (Exception e)
                TextWriter tw1 = new StreamWriter(logpath + "
exporterror.log", true);
                tw1.WriteLine("Exception when export report: " + e.Message);
                tw1.WriteLine(e.StackTrace);
                tw1.Close();