Yahoo Messenger keeps quitting on me but only when I try to send IMs what should I do?

So after I try to send an IM I get a pop up and then I click. Messenger disappears and the smiley on my screen still says its on when its not. Before it quit the first time me and my friend were messing around with IMeviroments and just chatting. So Then after we tried to bring up the Pop-Tarts one it quit unexpected and now thats what it keeps doing. I'm pretty sure it was nothing I hit accidentally.