1534376 - Error: Could not load file or assembly 'log4net'...

• Using CRVS2010
• There is no error if the project's platform target is set to x86
• Using 'Any CPU' or x64 results in the error;

ASPNETCOMPILER : error ASPCONFIG: Could not load file or assembly 'log4net' or one of its dependencies. An attempt was made to load a program with an incorrect format.

• CRVS2010
• VS .NET 2010

• There are two 'versions' of log4net.dll
• One is registered in the GAC_32 (x86 processor architecture version) and one in GAC_64 (AMD64 processor architecture version)
• Using the wrong log4net.dll will cause the error
• Also, see the forum thread Could not load file or assembly 'log4net' or one of its dependencies for a possible solution

KBA , BI-DEV-NET-SDK , .NET SDK / COM SDK , How To

SAP Crystal Reports, developer version for Microsoft Visual Studio