Installing OpenVZ on Debian - VFS: Cannot open root device

I'm rather new to both Debian and OpenVZ and have been struggeling with a problem for which I can not find a solution. The problem is not so much an OpenVZ problem but a kernel configuration problem. I can't imagine that nobody has ran into this problem before or maybe I'm just plain stupid, but thusfar I haven't been able to find some concrete information anywhere.

On a fresh installation of Debian, I installed OpenVZ following the wiki guidelines "Installation on Debian" (http://wiki.openvz.org/Installation_on_Debian). It is a straight forward aptitude install (aptitude install ovzkernel-2.6.9) from the stable debian repository (deb http://debian.systs.org/ stable openvz). When I reboot my system, it halts with the following message:

VFS: Cannot open root device "sda2" or unknown-block(0,0)
Please append a correct "root=" boot option
Kernel panic - not syncing: VFS: unable to mount root fs on unknown-block(0,0)

Has anyone seen this or a similar problem before and found a solution for it? If so, I very much like to hear about it.