Did you actually install the desktop?
I think you have to do something like this as root:
apt-get install ubuntu-desktop
(At least that's what you used to have to do. Not sure about how 9.10. works)
You also have to get the nxclient, nxnode, and nxserver debs from nomachines.com, and install them (as root) with something like:
dpkg -i nxclient*
etc.
I usually install the distro on a spare machine at home, and generate a package list:
http://www.cyberciti.biz/tips/linux-get ... store.html
Then I use the list to bring the linode version back to something close to what you'd get with the install cd.