Now this was an interesting time for DotNetNuke. There was a build - 3.0.13 which was the first in providing packaged skins as part of the build. This really caused some challenges because while the skins were pretty cool, as you can see here, they tripled the size of the builds and it became simply too slow to install.
That build was fairly quickly whisked away, never to be made available again, as there were other issues with the build that made it not really viable to keep as a download.
This was skinning for DNN 3, which had a few changes, some of which caused the skins to break due to lack of backward compatibility.
DotNetNuke doesn't always hide errors too gracefully so it often freaks people out when they get these errors which for the novice, could perhaps make them think that it's broken the site, but fortunately it's pretty hard to break a site with a skin, unless you're using DNN 5... and that's another story.