I just posted about a PPA which has a fixed Light Themes package for Lucid, but that PPA doesn't have packages for Karmic and Jaunty and also that package replaces the original Light Themes.
Mohegan asked if we could upload a fixed light-themes package in the WebUpd8 PPA and so we did, but we tried to please as many people as we can, so:
the package was uploaded under the "light-themes-fixed" name and the themes are now displayed as "Ambiance-Fixed" and "Radiance-Fixed" in the Gnome Desktop Appearance dialog. That means that the "light-themes-fixed" package does not replace the original "light-themes" package so you can have both of them installed and use whichever you want. The original "light-themes" package is of course still available in the WebUpd8 PPA (for Jaunty and Karmic).