I'm having the exact same symptoms running 2.3.2 beta 1.
I did a clean install on a new database, uploaded my theme which was running fine on a local MAMP setup (OS X 10.5). Then I went in and created a couple of new pages with Spanish translations then logged out again.
All seemed OK, so I then tried to get another domain (I have multiple domains) to go directly to a Spanish home page by using the Spanish home-page url. This resulted on a 403 error as I'd forgotten that I'd reset the .htaccess to restrict things until I have the site fully online.
However I kept getting the 403 despite entering the correct password, so I reopened the .htaccess and started getting exactly the same results as jarop: The CMS load page just sits there forever.
I have noticed the browser status line reporting loding 48 of 49 objetcs, then nothing.
Removing session cookies makes no difference, but adding the line:
works fine. As soon as it's commented out, the symptoms reappear. Putting it back in lets me log in again.
I get the same symptoms on Safari 4 beta and Firefox 3.0.10 (OS X)