converting void* to managed object

void ListenerCallback(int msg, int p1, int p2, void* p3, void* cookie) 
{
    mController^ mlc;
    // unwrap the native object...
    if(cookie){
    GCHandle h = GCHandle::FromIntPtr(IntPtr(reinterpret_cast<void*>(cookie))); 
	try 
	{ 
	  // and cast the object back out 
	  mlc = safe_cast<mcontroller^>(h.Target); 
	} 
	finally 
	{ 
	   h.Free();
	} 
   }
}

The runtime has encountered a fatal error. The address of the error was at 0x71de2e63, on thread 0x1474. 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.