I\'d make sure you have the files that it\'s looking for to redo the kernel. If you\'re downloading a new one now, try that first...personally I don\'t recompile a kernel unless I need to.
Since this happens only while in KDE, it could be something related to the video driver. It\'s worth downloading and trying out. I had a problem where the computer would lockup whenever the monitor would come back on from being powered off (was random, and monitor always came back on fine, could see the screen as I left it, but PC was completely frozen). Turned out there was a bug with the combo chipset and video card I used. Solution? I disabled power management and just turn off the monitor myself, lol. Ok, basically my point is that it could be a number of things, even if it doesn\'t make sense.