When I want to play, I get that "Unknown error" in champion select and the game blocks and I must to leave. I get this error too when I want to leave a Queue or to entert in one, I see "Retrieving data from server..." and after that I see that "Unknown error" again and I can't play. I tried to use the "Repair" option, to update my videocard, to restart and reinstall the game, but nothing.
PLEASE HELP ME
When I want to play, I get that "Unknown error" in champion select and the game blocks and I must to leave. I get this error too when I want to leave a Queue or to entert in one, I see "Retrieving data from server..." and after that I see that "Unknown error" again and I can't play. I tried to use the "Repair" option, to update my videocard, to restart and reinstall the game, but nothing.
PLEASE HELP ME
I have the same problem and im really curious about what is the solution, casue i got no help and this guy neither. 
Same.
The best part is that little message encouraging you to http://i.imgur.com/CS22j1Z.jpg is a lie
http://forums.na.leagueoflegends.com/board/showthread.php?t=3364574&page=10
