One thing you can try is to uninstall the extension and delete the CSS Sculptor folder at:
C:\Users\[username]\AppData\Roaming\WebAssist\Expression Web\CSS Sculptor
The AppData folder may be a hidden, so you'll have to edit the preferences to show hidden folders if you don't see it.
After deleting the CSS Sculptor folder, try installing the extension again.
Also, are you using the same version of Expression Web 2 on both the laptop and the desktop?