noting it down here for myself and anyone who maybe looking for this. Here is a pretty notorious exception that often bothers people working in Crystal Reports, specially if your project is recently migrated to a newer version of Visual Studio. In my case, its from visual studio 2005 to 2013. Things did compile but upon running a report it crashed with the following horrible notice:
An unhandled exception of type 'System.IO.FileNotFoundException' occurred in mscorlib.dll Additional information: Could not load file or assembly 'file:///C:\Program Files (x86)\SAP BusinessObjects\Crystal Reports for .NET Framework 4.0\Common\SAP BusinessObjects Enterprise XI
I looked around on the net, there are so many different solutions that would work for some and wont for some others. The solution that worked for me is this: I just had to add the following tag in the yourapp.exe.config file: licy="true">0"/>
inside the "configuration" tag. Here the useLegacy* tag is imp.