Hi!
This is probably caused by corrupted models.pck/pkx. As mentioned in the v73 patch notes, the patcher can corrupt these files now since we've exceeded the total size limit for them. Check the size of your models.pck/pkx. If they are nowhere close to 2GB, then they're corrupted.
What you can try:
a) Verify the files from the patcher. (This might not work, as the patcher might corrupt the models again)
b) Re-download the game and patch directly to v73 via auto-patcher.
c) Wait until this evening when I'll publish a new clean version of the game, and download that one.
I know a lot of people are having this issue, and it should be caused solely by the fact that we pushed too many files into models, when there wasn't enough space. Unfortunately, there's no way to resolve this via the patcher (the patcher can only add files), that's why all of the people with this issue will have to redownload the game or the files.
