I have have the new theme working on IE/Mac. If it's working on the old Mac version, I can only assume the latest PC version would render it fine.
If you don't see the user login block, scroll down to the bottom of the page.
The user login block is now located on the right. It's size was apparently breaking the theme, but this isn't an issue on the right side. All the world loves a workaround!
I've looked at the site in IE/Mac, Safari, Firefox, Camino and the whitespace/left column dropping issue is gone.
I created this new thread to report any theme problems you're experiencing with the theme. Just leave a comment with what's going on and the browser and version you're using, as well as whether you're on xp, osx, linux, etc.