It could be caused by a problem with the pilot campaign file. Could you check the one in your pilot's folder? If it's really big, then it's the same problem as I had (thankfully,
after I had finished the campaign and went to replay Universal Truth!).
You can see more about this specific problem
here. If it's not that, then maybe someone more knowledgeable may be able to shed some light over this.
In either case, you should generate an fs2_open.log by running the debug build and trying to play Universal Truth, and then post it here.
Here's instructions for that if you don't know how.