I'm pretty sure dropbox does file versioning, so you should be able to revert to an earlier (uncorrupted) version of your file. Tell me if that works for you, b/c I use dropbox+truecrypt for hosting my super important docs...
To get a previous version of a file, login to Dropbox.com, browse to the file you'd like to get a previous version of, then hover over the file and click the blue arrow on the far right that'll appear beside the file change date. This menu lets you, among other things, restore old versions of the file. Select the "Previous Versions" button to see all of the versions of the file from the past 30 days on any free or paid account, or if you have the packrat upgrade enabled, then you can see unlimited previous versions. Hope that helps!
I wish I found out about this within 30 days of my file getting corrupted. Strangely enough I posted my issue on the Dropbox forums and a Dropbox admin didn't mention this, he just said it's a problem on Keepass' end.
I use dropbox on multiple computers. one of the computers is running jungledisk to backup whole dropbox content. The problem is both services work on top of amazon cloud but I will eventually resolve this issue too.