[newbie] xlib problems

[Michael Dolan]

hi  today i tried to install mozilla M18 for the first time today but i
get this error message when i rin the installer

[root@CO3005336-A mozilla-installer]# ./mozilla-installer
Xlib: connection to ":0.0" refused by server
Xlib: Client is not authorized to connect to Server

GtK-WARNING **: cannot open display: :0

any ideas on how to fix this????