I don't think it is ever possible to get past that login screen. You can only get in if you are auto-logged in based on your identity at evcforum.
This was changed a while back (maybe about 1 month). Is there any chance that your browser cache has a copy of the previous version of the applet (from before, when it did allow use of the login screen)?
If you are seeing the login screen, then hitting your RELOAD-PAGE button is the only way to get into chat. If there is a way to force reload, try that to be sure you have the latest applet version.