"Redirect Loop - Redirection limit for this URL exceeded" error when I try to log out/register

Hi there,

I'm using Drupal 6.10 on a shared server.

When I accessed the site (in Firefox) yesterday, at first everything was fine. I could navigate around and everything worked, until I tried to log out. When I click the "log out" link, (www.mysite.com/logout) I get the below error. The strange thing is, after that, none of the pages worked at all, apart from the front page!

"Redirection limit for this URL exceeded. Unable to load the requested page. This may be caused by cookies that are blocked.

The browser has stopped trying to retrieve the requested item. The site is
redirecting the request in a way that will never complete.

* Have you disabled or blocked cookies required by this site?

* NOTE: If accepting the site's cookies does not resolve the problem, it is probably a server configuration issue and not your computer."

Then I opened IE and to start with everything worked. Then I clicked "register", and got the same error. Once again, everything stopped working except the front page after that.

So I tried Google Chrome. Same story. Works fine til I click register, then everything breaks.

I tried disabling drupal's clean URLs, but that didn't help.

Any suggestions?

Thank you!