I’m running into the same issue on my blog. I went and updated the jquery file to the newest version (1.4.1) of jquery and that seems to solve this issue. Is WordPress 2.9 shipping with bad jquery?
This was bugging me for a while – but the problem on my end was plugins. I had to disable them (by removing the directory via ftp), sign in, and re-enable them. I tried re-enabling them one by one to figure out which was incompatible… but when adding them back in they seemed to work.
