People are apparently still having problems applying skins to their blogs. In my experience, the problem usually boils down to one of these:
1) They don't have a Blogger-powered weblog. BlogSkins.com only supports applying skins to Blogger-powered weblogs through the Blogger API.
2) Their settings in My Blogs are wrong. If your Blogger Username or Password is wrong in My Blogs, the skin application will fail.
3) The Blogger API won't work for your account. Version 1 of the Blogger API just sometimes doesn't work for some accounts. There's nothing I can do about that. It's not under my control. Hopefully, the forthcoming Blogger API v2.0 will fix that.
4) There actually is a bug in my code. Possible, though not likely. Not because I'm a skillful coder, but because I've tested it. It works. It's not broken.
5) It actually did work, but they didn't login to Blogger and hit publish. I can't do this for you. You have to. Otherwise, the skin of your blog will look unchanged.
6) There's a bug in the skin code. I do my best to check for this, but some badly-coded skins do get through. And they won't Apply correctly. Check the comments of the skin.

Want a skin from this site for your blog, but applying it won't work? Best thing to do is to download the skin in Blogger format from here, open up the file you downloaded on Notepad or whatever, highlight all the code, copy it to your clipboard, login to Blogger, click on the Template button, highlight all the code of your existing template in there, delete it, paste the code from your clipboard, hit the save changes button, publish. Sounds complicated, but it's not. Try it out. It works. If it doesn't, it's because the code for the skin is bad. Check the comments first -- if it's bad, people will let you know in there.

Hope this helps.