A bug in WP Super Cache 0.9.3 caused problems with editing posts. It also showed the following warning if you had "Display Errors" on in your php.ini (you really should have that turned off on a public server!)
I have both problems fixed but I need feedback. Grab the development version from the download page. Copy the unzipped files into your plugins/wp-super-cache/ folder.
Optionally, or preferably, you should delete wp-content/advanced-cache.php or make wp-content writeable (chmod 777 wp-content is the easiest way) and visit the admin page where a new advanced-cache.php will be generated.
If all works, I'll release a 0.9.3.1 later with those fixes. Please reply here if it works for you or not!