Nobody can tell what class of what classlib you want, so there's nothing to tell you but that these two parameters of NEWOBJECT are in fact not optional and have to be passed in. So the actual error in your application code is the call of that code.
If you start the debugger at that point, you can see which code called in the stack window, can navigate to it and see that code.
To debug this, set a breakpoint before that call and see why the call has no values for the class and classlib.
Chriss