Custom cubemap not working? SOLVED!

[Cyberen]

So I have this cubemap I'm trying to make work in a new custom model. I know the problem isn't the file location because when I change the cubemap to a non-cubemap in the vmf it works fine. But I can't get it to work, not even with a test cubemap that's just 6 different colors. So I'm forced to conclude there's some essential step I'm missing when making cubemaps.

SOLVED: I just reinstalled VTFedit (132 to 133) and followed the steps and it worked! Apparently the program has bugs if used too much!