I had this happen to me a few times last night. I had two cases....

1st, I failed the quest to get to the planet within the 10 turns and got an strange message that was similar to an XML code within the description of the failure. 

2nd, I got an message from the Cravers, and again it was an XML code regarding diplomacy.

Both times when I got to the next election, it would not let me continue to the next step and had to alt-f4 the program. Then as soon as I re-loaded the latest save, it worked just fine until the next error.