For whatever reason, the Ubuntu 9.10 Server installer doesn't seem to detect the correct video mode when running over the HP LO100 virtual KVM. You can fix this by adding vga=771 to the installer kernel boot parameters.
1) Boot the Ubuntu install CD or image using physcial or virtual media
2) At the installer boot screen, select your language and press enter.
3) Press F6 to bring up the "Other Options" menu and then hit esc. This will expose the kernel boot parameters.
4) Append vga=771 and press enter
Your final boot parameters will look like: