I've had the problem before, except it would kill both my keyboard and mouse. It turns out for me that a piece of software that interacted with my UPS was being flagged by X-Trap as "suspicious" and probably shutting off the keyboard and mouse as some sort of defense mechanism. As soon as I disabled the software, LaTale behaved again.
What's happening to you guys could be something similar. Try going through the applications you run (Hijackthis
can put them into a nice list for you) and killing the non-essential ones one by one in Task Manager. If the game starts behaving again after you kill a process, then you may have had the same problem I had.