I have exactly the same problem - but only on Vista. I do exactly what tatts suggested - just open the Help file from Windows and everything is fine.
I've only had Texture Maker (V3.1) for a couple of weeks and it seems to be a very nice piece of software. Some of the documentation seems to be out of date and presumably refers to an earlier version, but with a bit of experimentation and practice I can easily produce a variety of realistic textures, heightmaps, normal maps, etc. Definitely worth the price.
And don't forget to download all the tutorials from various sites before they disappear.