Welcome back, no need to apologize. We used the time to release SDK 4.0.1516, wherein, among other things, we fixed the wrong format string. So now you can finally see the error message in all its glory.
Concerning the resolution of the underlying problem, I am afraid that I have no new insights: I cannot see anything wrong with your NxLib tree. And with the firewall deactivated, there should not be anything stopping you from opening the projector.
As far as the C57 is concerned: the C series uses the GigEVision protocol to communicate. The same protocol is also used to communicate with the cameras on the X36, and those seem to be working fine. But the X projector uses a different, proprietary protocol.
Can you run any of the other examples and see if they work, maybe try the Python example nx_simple.py?
Since the issue seems to be network related: could you provide packet captures, e.g. using Wireshark, from opening the camera in NxView and NxSimple? You can message them to me directly to avoid information disclosure.