Right outside of the main REPCONN headquarters, I came across a lost Brahmin running around randomly. I chased him and he eventually caught up to his merchant. I tried to purchase from the merchant, but either as soon as I click Accept, or immediately after the sale, the game crashes (CTDs). It doesn't seem to matter what I buy, although depending on what it is sometimes it crashes right as I click Accept, and other times it's shortly after closing the sale window.

It's one of the relatively few issues I've run into so far.

Phenom II X4 CPU
4 GB DDR3
Two HD5870s in Crossfire
SB X-Fi Titanium Fatal1ty
Windows 7 64-bit

This is becoming a known issue. You are buying duplicate caravan cards OR one of the caravan cards you are buying is 'bugged.' Posts are coming in so fast that this, and most issues, are easily missed. Just save before you trade and try to make sure you dont buy duplicate caravan cards for now.