Need a help with .Net 4.0 internal error

Faulting application desktop.exe, version 13.1.23.7, stamp 51a7c19a, faulting module clr.dll, version 4.0.30319.269, stamp 4ee9ae83, debug? 0, fault address 0x000c7402.

Tried turning off the concurrent Garbage collection with <gcConcurrent enabled="false"/> added to app.config file.

Need help, we were planning to release our current version this week, this is a show stopper issue.

The issue started occuring after upgrading from previous version that was using .Net 3.5

Need help ASAP.

Thanks,

VV