Hi, I've had exactly the same problem (crashed occured randomly, some times even after week). After reinstall to amd64 everything seems to be fine.
Currently running: Debian GNU/Linux 5.0 linux-image-2.6.26-2-xen-amd64 (2.6.26-15) xen-hypervisor-3.2-1-amd64 (3.2.1-2) Regards, Jozef Švec <jon...@gmail.com>
