3ds Max :: Error Message / Unknown System Exception

Recently I found that I couldn't import a .bip file onto my CAT rig. Here's the error message:

Unknown system exception

and highlights the following line of code:

local liindex = FindCATNode catNode;

I've tried several things and copy/pasting the error to google only gives a single page of results, with very few possible solutions. There was one saying I should replace the highlighted code with a different piece of code and restart max. this just changes the error message.

Another solution was to get max 2011 32 bit, save it there and open it up in 2012, however other posts had the exact same problem with importing 2011 files into 2012. so that also doesn't seem like a working solution.

That's about when I reached the end of the page... Could it be that importing the original BVH onto a biped and exporting the animation to .bip caused the .bip file to get corrupt or something? I've tried loading the BVH file onto my CAT rig directly, but this just crashed max.