Targeting .NET 3.5 does not tell me what version of .NET you are using as it could be 2005(?), 2008, 2010, 2012, 2013. Not all of those are supported with CR XI R2. See this wiki for more details:
To me the process of converting reports from RAW to PDF format is extremely inefficient and doing a direct export to PDF would be the way to go. Perhaps this will be worth a test with a very simple one line app (as long as you are in a supported environment):
CrystalReportViewer1.ReportSource = <path to a report>
Let the report prompt for DB logon. Once the report is in the viewer, export to PDF. I realize you may not want the viewer in your actual app, but this one line app will show you the performance of direct export to PDF.
- Ludek