When I try to get into the edit mode all the controls disappear and I get an empty page with the logo on top. I have to check out and log in again. I am running the actual moodle 1.8 build. An 1.7+ installation on the same machine (another domain, another database) works flawlessly.

And the actual Moodle 1.8 build on my local computer (XP SP2, Apache 2.2.4, MySQL 5.0.33, PHP 5.2.1 & PHP 4.4.5) runs without that problem.