I have come across this problem on several forums, and on my own box. After a time-consuming investigation I discovered that it seems that several publicly available RPM files for lnstalling xorg-libs/xorg-libs-devel have a non-compatible libXext.so file. As far as I can tell this seems to be on X86_64 systems. Specifically the libXext.so (.6.4.so) located in /usr/X11R6/lib/ seems to be a problem (the one in lib64 seems to link ok, but just deleting the one in lib doesn't seem to work). After attempting several supposed solutions I DL'd, & compiled the latest xorg. Prior to running 'make install' I moved /usr/X11R6 to /usr/X11R6.old, and created a new empty /usr/X11R6/ directory.
This breaks stuff, specifically a lot of your X applications, but if you're patient you can re-install them from the rpms on your source CD.
I just rpm -i --force (glib/gtk/gtk2, their devel packages, etc.).rpm and a few others and that gets most everything back up and running. (make sure to run ldconfig)
If you wanted to be less messy you could just compile your current version of xorg from the sources and copy the needed files, but what fun is that?
After all this mplayer compiled and I'm watching a DVD on it now!
After some tweaking most everything else is working too.
Thanks for your time!
Eric The Leg
If an infinite number of monkeys type 'rpm -i' on an infinite number of Linux boxes over a long enough period of time, one of them will one-day get something working
A-64 3200+ Nforce 4 Socket 939 o/b sound o/b network 1GB Ram, Nvidia Ge-Force 6200, Fedora Core 2