Widgets totally uneditable

Hello.
I’m running WP 3.0.1, on a site I launched about two months ago. I tried to open one of my sidebar widgets tonight, to change something, and it wouldn’t open. I then discovered that I couldn’t drag any widgets, either. Suspecting a possible conflict with a plug-in, I deactivated them one at a time, but no luck there. Here are the plugins I have activated:

AddThis Social Bookmarking
Akismet
AllinOneSEOPack
AVH First Defense Against Spam
Comment Luv
Display Widgets
Google XML Sitemaps
Mingle Forum
MultiFeedSnap
Nofollow Free
PubSubHubbub
Robots Meta
Simple 301 Redirects
Subscribe Here
Tweet Meeme Retweet Button
W3 Total Cache
Wordpress.com Stats
WP-cycle
Wp Security Scan
WP Touch

It’s been a couple of months since I had occasion to go into my widgets, so I have no idea how long this problem may have existed. Everything is functional, but not editable.

As a point of interest, I originally started out with the Display Widgets to set my widget displays by page, and about a month ago, had changed to Widget Logic. I didn’t like it, however, so I deactivated it and returned to Display Logic.

My site is http://docsheldon.com.

I’d really appreciate any advice you may be able to offer.

Thanks!