Problem with kdm 3.5 not starting

[David Goodenough <david.goodenough@btconnect.com>]

I have a sacrificial machine which I keep fully up to date with  unstable.

This morning KDE 3.5 arrived, so I installed it.  It seems to work just fine 
if I start it with startx.

BUT kdm will not start, and in the file /var/log/kdm.log there is an 
error saying the on the X command, the -br option is not recognised.

I have tried purging kdm and reinstalling to see if any of its config files
needed updating, but that that did not cure the problem.

The only "odd" thing about this machine is that it has a very old S3
graphics chip, which is not supported by x.org.  So I use the old S3
XFree86 xserver.  

I have so far been unable to find where X is being invoked with the
-br option, any pointers would be gratefully accepted.

Thanks

David