The Problem:
Auto-installing Skin/Theme files are downloaded as zip files.
The Cause:
SP2 appears to be common factor here, but some people report no change after SP2.
What's happening is this... self installing file extension for most skinning programs are simply renamed ZIP archives. For some reason after SP2 is installed on XP, the extensions are renamed back to .zip when downloaded.
But it's easily fixed.
The Solution:
Step 1. File extension must not be hidden. If you're unsure what that means, open Control Panel > Folder Options > View tab > "Hide extensions for known file types" should be un-checked.
Step 2. Right-click the file and select Rename. Change the zip part of the name to the proper extenion. Example; skin1.zip = skin1.wba (for a WindowBlind skin)
DesktopX Themes = .dxtheme
DesktopX Objects = .dxpack
WindowBlinds = .wba
LogonStudio = .logonxp
BootSkin = .bootskin
CursorXP = .CurXPTheme
IconPackager = .ip
If you get a warning about changing the extention, click OK
Step 3. Double-click the renamed file.