unwrap causing crashes?

I’m having an issue trying to learn how to UV wrap in blender. I’m using 2.49, which seems to go about UVwrapping differently than the versions used in pretty much every tutorial I’ve found. I’m a super novice when it comes to 3D, and I’ve followed the sub-surf head modeling tutorial on Blender.org to create a head.

Now I’m trying to unwrap it, and I went ahead and cut myself the seams

This is a picture of my earliest seams. I have many more now, but this is the image I had handy online, 'cause I’m blogging about it and I wanted to show my 1st step.

Anyway, after I finished I discovered I have another issue. I created part of my head by duplicating and mirroring the other half of the head. So from certain angles you can see right through it.

At first I didn’t think anything of it, because I assumed once I got a wrap of it, it would work fine. (works fine when rendered with basic materials)

However, when I press U to unwrap, Blender just freezes. Its a soft crash, as I can still minimize/maximize the problem, and it doesn’t turn to “not responding”, however my mouse disappears every time I move it over the application, and I can’t press any buttons or get any sort of response from the program itself. (other than closing if I press the red X)

anybody know whats wrong, and how I could fix it?