Ladies and Gentlemen, I have figured out the issue.
1st, open REGEDIT and go to this key
Make sure the string "Cache" string equals C:\Documents and Settings\~user~\Local Settings\Temporary Internet Files\
Then go through explorer and make sure that path actually exists.
Now go to windows control panel and open internet options, click the settings button on the general tab as shown here http://www.hostsalive.com/screens/20100615-75s-47kb.jpg
Then in the resulting window, make sure "current location" equals that registry setting. Use the "move" button if it doesn't.
I rebooted the pc and reinstalled avant, and BAM it works. Seems like Avant had nowhere to keep temp files, so it was crashing.
I found this because every time I opened word I got an error about cannot create working file, etc. So I googled it, this same procedure fixed both issues.
Thanks to the avant people for putting up with me