Hi,
I think you should comment that line and test it (after backing xorg.conf =
as now Xorg is supposed to work with built-in configuration.
You may also try to mv xorg.conf to xorg.bak and check if it comes clear so.
By my (single) box, it works great without xorg.conf (on a crt Gateway VX900) ...
Excerpt from /var /log/Xorg.0.log:
X.Org X Server 1.7.7
Release Date: 2010-05-04
X Protocol Version 11, Revision 0
Build Operating System: Slackware 13.1 Slackware Linux Project
(...)
Using default built-in configuration (30 lines)
(==) --- Start of built-in configuration ---
(...)
But that's a very specific setup that's you have and I'm not a Xorg guru, so I hope nevertheless it's help...