We've changed the location of the forums from http://forums.mortalis-guild.eu to http://www.mortalis-guild.eu/forums/ to fix a problem with a broken white page occasionally appearing very briefly when using Mozilla Firefox, which occurred ever since the forum software was updated 2 day ago.
We don't know the cause or why it only happens in a certain browser but all should be working fine now with this change. This will also be why your browser is prompting you to store your member username/password information again due to the change in the address. Thanks!