In the end I found out what was causing my troubles... a single .dxf file that had been generated from a plate that had not been assigned a model role (none). After a good hour of filtering down through my layers of folders, (making copies, deleting layers, and reloading the good file paths), I found the file, deleted it and everything returned to normal.
As previously stated, I did try multiple resets and re-installs, which in my opinion is a moronic fix for a problem. If you don't know what your problem is to begin with then how are you going to avoid it for next time? Not to mention the time wasted setting up profiles again (even after making backups, not all of my settings made the migration).
The help I got from Autodesk was pathetic. All they suggested was, again, to do a reset/re-install. In the time between their initial emails and scheduled video consultation, I found the problem, fixed it and when I gave them an explanation as to the problem/solution they were genuinely lost for words. It was as if they had no insight into this problem and just took my feedback "into consideration". Paraphrasing here: they said "Oh, okay, well we can't help you now, just don't do that again".
Words cannot explain how livid I was about this whole situation and how such a small thing, one file!, can cripple an entire program.
I guess I've learned the hard way to double check model roles before exporting...
