Make sure X11 is installed.
I assume you are not running a graphical windowing system like GNOME or KDE. The only time I see this problem when these are running is if I am root and I don't have a DISPLAY environment variable set.
You'll need to run an X server on another computer, and export your display to that machine. That way the installer and associated programs that it launches has a screen to use.
See this thread as it relates to your problem. http://www.linuxquestions.org/questi...wading-127682/
I also wonder what distro you are running?