I recently installed Crystal Reports 11 for Microsoft Developer Studio 2010 using the CRRunTime_32bit_13_0_5.msi on a Windows 7 64 bit system. I then created a C# (.NET 4.0) assembly with the report viewer then referenced this assembly from another C# (.net 4.0) assembly.
When I build the assembly that references the CR assembly I get the following message: No way to resolve conflict between "log4net, Version=1.2.11.0, Culture=neutral, PublicKeyToken=669e0ddf0bb1aa2a" and "log4net, Version=1.2.10.0, Culture=neutral, PublicKeyToken=692fbea5521e1304". Choosing "log4net, Version=1.2.11.0, Culture=neutral, PublicKeyToken=669e0ddf0bb1aa2a" arbitrarily.
I found this blog post:
http://scn.sap.com/thread/3167651
but the fix there did not fix my problem.
Note all my assemblies are build for .NET 4, but the references to the CrystalDecisions assemblies are showing as .NET 2.0 even though the path to the assemblies shows as a 4.0 path (C:\Program Files (x86)\SAP BusinessObjects\Crystal Reports for .NET Framework 4.0\Common\SAP BusinessObjects Enterprise XI 4.0\win32_x86\dotnet)