Misc config problems
This is a random list of problems I got and how I fixed them.
Illimitux plugin in Firefox is forcing network.http.sendRefererHeader to 0 (always resetting it to 0) in order to block sending referrer when browsing, preventing some websites from working. Disable this plugin to fix the problem.
Apache server: RedirectPermanent of other redirections in a .htaccess are not working if you don't enable them in the configuration with “AllowOverride All” (and not “None”).