Hmmm..... it may be something to do with XP, although I suppose other people use XP and uv mapper. I dunno. What I can tell you is that I tried Lith unwrap at one point and gave up on it. Maybe it's me but I found it almost unusable. For me, steve's is the only one to use. Another thing is, if you're seriously getting into it, you may want to consider uv mapper pro at some point. It costs $50, but it's worth every last cent. Best $50 I ever spent. Obviously, you don't want to get pro until you get the free one working first, but keep it in mind for future use. mac