Can't get text login in RHEL 4 by commenting out prefdm in inittab

I am upgrading a system from RHEL 3 to RHEL 4 (Update 3, AMD64).

Previously, we commented out /etc/X11/prefdm at the end of
/etc/inittab, so that after bootup, we got a text-screen login. We
then logged in, and ran startx manually (this was done due to a 3-party
application that has particular colour requirements).

In RHEL 4, if I comment out prefdm, I do not get any login prompt.

Anyone know why?

TIA
Mark Bergman

.