do you have a network card configured?
at boot do you gat a failed message in red typeface?
you can edit /etc/hosts with vi, or gedit or kedit if you use X, but it likely wont help.
if you have a NIC, and RH thinks you do, it's trying to get an IP address using DHCP, and should give you a failed message at boot (before X starts)
Let me know about above Q's