Hey There,
I experienced this problem when I updated a site from 2.6 to 3.0. The following things did not help:
– deactivating all plugins
– switching to the default theme
– upgrading to 3.0.1
– messing around with tiny_mce_gz.anything
– turning off compression
What finally solved the problem:
– Downloading a fresh copy of the entire wordpress file for 3.0.1 to my desktop and copying the tinymce folder from the freshly downloaded version of wordpress to /public_html/wp-includes/js/ on my site. Apparently, we had an /tinymce file, and overwriting it with a fresh version seemed to do the trick. If you’re still running 2.9.2, you might download the old file for safekeeping, then try uploading the /tinymce file from 3.0.1, just to see what happens. If worst comes to worst, you can just re-overwrite the new file with your copy of the old one.
Hope that helps.
