I have similar issues. Am new to antiX (used as rescue disk since M8) and MEPIS, but not so new to fluxbox and icewm.

Can only get RutilT to recognize my card. And it won't save the profile which requires adding the network each boot. Frustrating.

Also asks for screen res at boot up. Hit enter for default works. Would like default to be default without intervention (hitting enter) after initial setup.

Am pleased with antiX otherwise. I, too, installed on PIII 256MB. Breaths new life into an otherwise rather large paper weight/door stop. __{{emoticon}}__

For screen resolution, you will need to add something like vga=normal or vga=788 or whatever for your screen at boot menu.

Try running rutilt as root and see if that saves the network pfofile, or manually add it to /etc/network/interfaces (as root)