The page is not redirecting properly
From MozillaZine Knowledge Base
When a webpage redirects you in an endless loop, Firefox will display an error with the message, The page isn't redirecting properly. Firefox has detected that the server is redirecting the request for this address in a way that will never complete.
This article describes a few things that you can do to stop these errors.
Check for bad bookmarks
If the problem is occurring on only selected web sites, you may be using bookmarks made from web pages that saved parameter information that no longer produces a viable page.
To fix bookmarks,
Firefox on Windows:
Firefox on Mac OS:
Turn cookies on
Firefox must be set to accept cookies from websites.
Note: In Firefox 3.5, if you do not see the "Accept cookies from sites" option in the Privacy panel, set the "Firefox will:" option to "Use custom settings for history".
You may have data in your cookies that the site doesn't expect. To clear this data:
In Firefox 2.0 and higher:
In Firefox 3.5:
Note: In Firefox 3.5, if you do not see a "Show Cookies..." button, set the "Firefox will:" option to "Use custom settings for history". Alternately, click the "Remove Individual Cookies" link (if present) to open the Cookies window.
Enable referrer information
Check that network.http.sendRefererHeader is set to 2:
The problem could simply be an error in the website's coding or server configuration. Contact the webmaster for assistance.