Modeling woes (UVW + vertices error)

I made a few small changes to the eyes and nose to one of oldflash's heads (with his permission of course), but I'm having a little bit of trouble getting it into the game properly.

First of all, there is a pretty sizable hole in the model's neck, as you can see in this screenshot. Another problem is that there is hole for where her hairband was, and the texture has gone crazy. (On oldflash's original model he had done away with the hair bun and remodeled the hair to be rounder.) A third error is that there are some stray vertices way off in the distance. I assume that this is where that chunk of her neck or where her hairband went.

None of these problems can be seen in Gmax. This leads me to believe that the errors have to do with either exporting the head model from Gmax or from recompiling it with Taina's replacer tool. However, after encountering these errors I tried reexporting the model from Gmax and recompiling it with Taina's replacer tool several times, but each time I had the exact same problems. Also, I when Taina's replacer tool asked for the original version of the model, I tried pointing it toward the one straight from the game, rather than oldflash's edit of it, but I still got the same errors.

I was following this tutorial.