I’m having the same issue trying to delete a page. I just went through the 2.0.3 upgrade on one site and had moved wp-admin wp-include and wp* in the main folder got moved to a bkp folder (wp-content overwrote everything) unfortunately, so I’ve had to recopy my template and plugin files. But, now that I’ve got everything straight, I can’t delete a testing page that I wrote after the upgrade. (I’m logged in as admin…) I saw a reference when this has come up before that perhaps not all the wordpress files had been removed before upgrade, but it seems that was fairly thoroughly done.
I did the database upgrade on login, everything LOOKED to go correctly.
I’ve even gone through a second time and blew EVERYTHING away and re-copied the files and that doesn’t seem to do it. I thought maybe there was a browser cookie issue, tried another browser to login, still no luck. Any other suggestions would be welcome.