Spontaneous reboots on 5.99.59/i386 on a Thinkpad X41

[Moritz Wilhelmy <ml+netbsd%wzff.de@localhost>]

Hello,

My Thinkpad X41 keeps rebooting itself (i386/5.99.59). It usually
happens when I try to start urxvt, after the program is already running
but just before it tries to create it's X window. Other X applications
like xterm work. This also happens if I use /netbsd.old as kernel (also
5.99.59, but a bit older). This happened out of the blue. I remember
being able to use the very same urxvt on the very same kernel a few days
before it started rebooting.

This is completely weird, but one reason I can think of is that the
filesystem is hosed by my previous experiments with fss(4).

Has anyone experienced similar problems? Can it a hosed filesystem
really be the reason for this?

Thanks,

        Moritz