Suddenly unable to move or type in game

Hello, just yesterday in a dungeon I was mid boss fight when suddenly I couldn't move or anything. I couldn't cast, type in the chat box, or anything. My first reaction was that maybe my keyboard was dead, but I could still type in other programs, and move my mouse. When I tried to exit the game, the confirmation box came up, but it was unresponsive. The only way to fix it was to restart the game through Task Manager.

It happened again today, and as before, it was in the middle of a boss fight. The worst part about it is that I can see I'm not disconnecting or lagging - everything is proceeding around me as normally - and there's no way I can indicate to my party what's happening. Has anybody else had this problem before? Is there a way to fix it?

Had it too yesterday. Submitted a glitch ticket in the appropriate subforum.