Problems with export to PDF from C# code

I have problems export a Crystal report to pdf from code. Generating with database on accept is working as planned. But when I select production database (software on the same server) then I have problems with a few reports? The application just seem to hang on this line of code

myReport.ExportToDisk(ExportFormatType.PortableDocFormat,@"c:\temp\name.pdf");

Configuration Windows server standard with installed:

• Crystal Report 2008 Runtime SP3
• SAP Crystal Reports runtime engine for .NET Framework 4 (32-bit)
• SAP Crystal Reports runtime engine for .NET Framework 4 (64-bit)

I also tried different formats (txt , excel) but the same problems.