Yes we have had major cookie changes in the past few days so clearing your cookies and cached files will solve all of these issues. Of cource you have to start from scratch on some of your settings (lang, forum groups).
So everyone semi-understands how this is working...
One login for all *.armorama.com domains (not included would be armorama.co.uk - although now there is only one login for that with the "www" version as well).
Different cookies are still in place for the language interface setting. So if you set your language to something else and change domains the interface language will change with the domain.
The MULI-Language setting is now global across all *.armorama.com domains. This is the setting that shows more than a single language in forums.
That is all.

Jim