Can't get XFree86 to work with SiS chipset

[Christian Call]

I just installed Red Hat Advanced Server 2.1 on a machine that has a SiS 661FX-series video chip set in it.  Unfortunately, I can't get XFree86 to work.

No matter what SiS driver I choose in the Xconfigurator, I always get a message saying that there was a problem with my X configuration.
 
I tried downloading one of the precompiled drivers from Thomas Winischhover's site, but I'm not having any luck with that either.
 
Is there a way to get AS 2.1 to work with this video chipset?

Thanks for any help...

-- Chris