Winfrom application(4.5 framework ) convert 32 bit 64 bit facing FatalExecutionEngineError

Managed Debugging Assistant 'FatalExecutionEngineError' has detected a problem in 'C:\SnapDPL 64bit\Code\Source\StagingArea\DataProcessLogic.Studio.exe'. Additional Information: The runtime has encountered a fatal error. The address of the error was at 0x9b68b4ae, on thread 0x6698. The error code is 0xc0000005. This error may be a bug in the CLR or in the unsafe or non-verifiable portions of user code. Common sources of this bug include user marshaling errors for COM-interop or PInvoke, which may corrupt the stack.

some times like that i am getting

System.NullReferenceException' in System.Windows.Forms.dll Additional information: Object reference not set to an instance of an object.

An unhandled exception of type 'System.ExecutionEngineException' occurred in mscorlib.dll