w3wp.exe crashes in un-managed code dll for ASP 64 bit Classic web application on IIS 8 and (Windows 8 / Windows Server 2012) machine

Original post is @ http://social.msdn.microsoft.com/Forums/en-US/netfxsetup/thread/c83c7549-483d-4701-a89d-04d4b339b0e0

HI

I am facing issue while trying to run 64 bit web application on IIS 8 and (Windows 8 / Windows Server 2012) in Classic mode. Every time app pool stopped due to w3wp.exe crash.

In IIS manager, I also set "enable 32 bit application" flag to "FALSE" in app pool setting to run 64 bit web application.

Following are some event log messages I am getting. 

Error 1:

Error 2: 

From Event logs, crash location is not clear so I debugged the web application and try to check the output window of Visual Studio 2012 at that time i found that all the managed code DLLs are loaded properly but when one of Managed code DLL trying to load un-managed code DLL THE w3wp.exe crashes and application pool stopped working.

What works:

1. 32 bit version (Classic mode) of same web application is working on IIS 8 and (Windows 8 / Windows Server 2012) machine.
2. 64 bit desktop application (using same DLLs as 64 bit web application) is also working fine on (Windows 8 / Windows Server 2012) machine.
3. Same 64 bit web application is also working fine on IIS 7 (7.5) on 64 bit Windows 7, Windows Server 2008 R2 Machine.

Can some one please help me out?

Thanks in advance.