Problem printing reports (Crystal Reports XI) using C# codes

Question

I have an application that basically grabs the crystal report specified and send it to the printer for printing. My working version was using Crystal Reports 8.
Recently, I'm testing to print reports created using Crystal Reports XI. I've included the new crystal decisions library into my project but whenever I try to load the report, I keep getting "Load report failed" error.

ReportDocument objDoc=new ReportDocument();

// Load the report
objDoc.Load(strReportFilename); <-- Error happens here!
...
...
...

// Print the report
objDoc.PrintToPrinter(int.Parse(copies), true, 0, 0);