I just upgraded WinAMP, both at School and at home. My problem is the version at school has problems with skinning. When I load a skin it will only skin the main window or playlist, depending on the skin.

Are you sure it isn't the skin itself. There are a lot of skins out there with only the main window skinned, the playlist and equaliser are left as default.

Yes, the skins work at home. I know because I use the exact same ones, and at school one or two will skin the playlist and the buttons on the main window, and nothing else.