It seems like Second Life is offline due to undergoing unscheduled maintenance right now. Latest updates check http://status.secondlifegrid.net/. I have not seen this Login Failed message for a while. On going discussions from the SL community about this can found on Plurk, Twitter, SLUniverse and the SL Forums. Hopefully logins will resume soon! 🙂
Login failed Due to system problems. logins to Second Life have been disabled until further notice. Please monitor the Grid Status page for updates.
Problems effecting logins, marketplace orders and SLwebsite services etc.
Daniel Voyager 