Hi, I've looked at your code and the problem seems to be the function prototype for the DLL function. Change this...
Code:
void __stdcall fnTesdDLL(void*);
#define PRAGMA_API fnTesdDLL;TesdDLL!fnTesdDLL

to simply this...
Code:
function fnTesdDLL(void*);

I have tested myself using my own callbacks and using your prototype singature gave me the crash. Use the lite-c function type.