Okay, so I just updated my files to X-Piratez 0.98D, and my machine still crashes on the Siberia Mission, even before it gets to the infantry inventory screen. I have been able to replicate this at least twice so I don't think it is coincidental. It may possibly be an issue that I am using a somewhat dated Nightly, but the game worked perfectly fine on 0.98C, so it may simply be an issue with the mission still.
I wish you luck in fixing this error, as from what I can gather it seems to be impacting many people.
Best of luck!