black screen problem

if i lock my computer with maplestory running, it "freezes" when i unlock it. i'm stuck at a black screen and am forced to restart. i didn't lock it last night and it still froze so i assume the screen saver/monitor turning off freezes it too. anyone else ever have this problem? i'm on windows 7 professional but i don't know if it's the problem.

edit: it just started happening after patch 0.78

Are you still using the RC? I've had some problems with Maple and Windows 7 myself.

nope. i'm using the retail version.

On a Mac running Boot Camp by any chance?