Google rolled out some changes to the HTML that runs Gmail in the last few days that rendered several of Better Gmail 2's features completely busted. (Yes, that's the technical term).
So I just posted a quick fix-it version 0.7.3.1, which includes changes from the very speedy and helpful Arend von Reinersdorff. (Arend is responsible for Better Gmail 2's most popular features, Folders4Gmail and Hide Spam Count, and I know--because users flip out the moment they stop working. Thanks, Arend.)
Sadly I had to remove several scripts which have not yet been updated to work with Gmail's new markup. Update, Thursday, March 5th: All scripts have been fixed in version 0.7.3.2, which is available now! Thanks for your help.
In the meantime, download the new fix-it version 0.7.3.2 using the Download button on the right, from Better Gmail 2's homepage, or just using Firefox's Add-on boxes' "Find Updates" button. Thanks for your patience with the broken features the last couple of days.