I had trouble loading from the 10.04 live cd, and finally gave up on the live cd.
No, I don't remember exactly what was wrong, but I've been using Linux for quite a while, a RHCE, UNIX since 1982, and the effort to fix it wasn't worth the time already spent. IIRC, it seemed like the live cd is a stripped down version of the distro install cd, and too much was missing for my system to run correctly.
Loaded from the regular Ubuntu distro and then ran the linuxcnc.org script to install on a already loaded 10.04 system. That worked just fine.