If I take a print-screen I get disconnected and a message with something like "hunk_allocate_memory: failed". I think it indicates that there is not enough memory left for a print-screen. Maybe the high memory use also causes laggs.
Guys, I hope I'll play soon with you. Now I seriously have no free time. You would think: "Harry! You are studying too much! Come and play! " But I have a gf now... hehehe