Holding the shift key bypassed the graphical bootloader and the installer worked correctly after that.
Note that for some reason the screen resolution was not set correctly and the installation progressed in 640x480. After the installation completed, I was able to have all the resolutions supported by copying the detected vertical refresh rate and horizontal refresh sync from /var/log/Xorg.0.log to the xorg.conf file. -- Fail to boot on a PIII with a 3DLabs Oxygen VX1 video card https://launchpad.net/bugs/62453 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs