My site runs two themes ... I user theme that I have built myself and Bluemarine as the admin theme. I was just changing the theme defaults today when I accidently clicked on a particular theme that was an evolution of my user but wasn't working properly. Two things happened:
1) My user theme has screwed up -- no big deal
2) I can't get into ANY admin part of the website. Any admin area I go to I get the following message:
Page not found
The requested page could not be found.
Albeit nicely displayed in the Bluemarine theme