Can't see Entry Editor after Upgrade from 4.23 to 4.25

Hi,

I upgraded from Movable Type Pro 4.23 to the open source version of Movable Type 4.25 and now I can't see the Entry Editor. I decided not to install the Pro version this time and do the open source version. Could that have broken it?

Here's a screenshot showing the other buttons and the missing editor:
http://i106.photobucket.com/albums/m260/ptepper/MT-screen.png

I've read these two threads:

http://forums.movabletype.org/2008/06/dialog-and-entry-editor-go-bla.html
http://forums.movabletype.org/2008/09/blank-entry-editor-other-javascript-problems.html

Neither solves the problem. They mostly talk about problems with cross-domain/cross-site scripting, but that's not the problem here - everything is under the same subdomain. I think it might have something to do with the upgrade and having the wrong JS files in either cgi-bin/mt-static or my.domain.com/mt-static/

I haven't noticed anything else being broken in the interface or my blogs; I've edited templates without a problem, and haven't see any JS errors in any of these pages. I've tried it in FF 3, IE6 & 7, and Safari (Windows), same problem in all browsers.

thanks,
-paul