Maybe If you are using GRUB, maybe you need to update your "linux-loader" the /boot/grub/menu.lst file(can be configured at /etc/kernel-img.conf) for the "GRUB":

Reboot in your new Debian Stable Sarge OpenVZ System

Now it's time to setup your VE's VEs with the minimal Debian-3.1 Template, create new one or download another precreated OS-Template.