Pretty much what it says on the tin - I had to reinstall my gaming machine and therefore reinstall WoW and all my addons. Since then, DBM hasn't loaded. I can go in and manually load the appropriate module for the instance, but it doesn't load itself. When I logged in, I remember DBM used to post a "welcome" message in the chat window that confirmed it was loaded - no sign of this since the reinstall either.
I installed via the Curse client and the only other addons I have are MogIt and Recount, both of which worked fine with DBM before I reinstalled. Is it something I've done in the process of reinstalling WoW/DBM?