X won't start after yellowdog install on newish iBook

[Richard D. Gill]

Hi

I have just installed yellowdog 3.01 on a partition
of my one year old iBook. Installation went really
smoothly (and graphically). However on start-up
X windows fails to launch and I get the following
mesages:

Using config file /etc/X11/XF86config
(EE) RADEON(0) Virtual height(0) is too small for
the hardware 128 minimum
(EE) Screens found but none have a useable configuration

In /etc/X11/XF86Config there is a section for the
screen which looks like what I actually have and
also a section for the monitor where some defaults
are written, I don't have a separate monitor attached
to the iBook. Could it be that XF86 thinks that there
is a monitor, and can't find one, and doesn't realise
that I want to have X on the screen of the laptop?
How to tell it what to do?

There is also a line at the top of the config file
with display 0 "Screen0" 0 0
which has suspiciously many 0's but I don't know
what ought to be here. "Screen0" does refer later in
the file to the screen I actually have.