This message comes up on export. No clue what it wants me to do. I've read that it's because of too many polygons but when I optimize the same thing happens. Anybody have any clue?

What are you exporting?

Meshes that are rigged to a skeleton/ armature/ bones need to be weighted properly. Those meshes get deformed ingame depending on the influence certain bones have on different areas of that mesh. You didn't optimize that mesh, you most likely killed the existing weights. You should do some basic tutorials on rigging and weightpainting in max for a better overall understanding. This is not ment offensive. I ran into the same dead ends back in the past. Do basic non modding related max tutorials and you'll be able to figure what is wrong by yourself on the run.

Ok, so no quick and easy solution then? I'll just file this one under 'too complicated for me' and move on. Thanks for the reply!