[Attack of the b-team keeps crashing]

I Know Tekkit fix your launcher so we can play !!!!!!!!!!

[Attack of the b-team keeps crashing]

Every time I go to click play on attack of the b-team it loads up the Mojang screen and then it brings me back to the launcher and wont let me PLAY!!!!!
Help Please
Its only doing this to the attack of the b-team server is it just down or am I experiencing diffficulties