Cookies in WP 2.3

I have 4 blogs under the same domain, three of which are using WP 2.2

The fourth is one I use for testing plugins and such and was updated to WP 2.3. Since updating it to 2.3 I can’t login because it claims “WordPress requires Cookies but your browser does not support them or they are blocked.”

Sorry but… both the cookies were cleared (and verified they were allowed in FF) AND my firewall was shut down and the problem still persists.

Any thoughts, bright ideas, or something. At this point until I learn what has caused this I won’t be updating my three active blogs.