StickDeath, I had the same error as you, also with RedHat 9.0. I had to install the Nvidia Linux drivers exactly as shown below to get Enemy Territory to work. Hope this works for you.
*** How to install the NVIDIA Linux IA32 driver
in Red Hat 9.0 ***
1. Verify that you have the following Linux modules installed:
Module Min Ver. Determining the Version
Linux Kernel 2.2.12 # cat /proc/version
XFree86 4.0.1 # XFree86 -version
Kernel modutils 2.1.121 # insmod -V
binutils 2.9.5 # size --version
GNU make 3.77 # make --version
gcc 2.91.66 # gcc --version
If you don't have any of these components installed
then click on the Red Hat icon, point to System
Settings and then click on Add/Remove Applications
icon. This starts the Package Management utility.
You can also type in redhat-config-packages at the
command line to start this utility. You will be
asked for the root password to continue.
Select the all the options from the Development
Tools and the Kernel Development sections. Click
on Update and then follow the instructions to to
install these components.
2. Download the latest Linux IA32 driver (currently
NVIDIA-Linux-x86-1.0-4363.run) from
www.nvidia.com.
3. With root or su rights, modify the /etc/inittab
file and change the line that says:
id:5:initdefault
and change it to:
id:3:initdefault
4. Exit the X server by rebooting and then login
as root.
5. Change to the directory where you downloaded
the NVIDIA-Linux-x86-1.0-4363.run file and run the
following command.
sh NVIDIA-Linux-x86-1.0-4363.run
Follow the instructions to install the driver. If
you have a new Linux kernal that NVIDIA's FTP site
doesn't have an interface for then the install
utility will compile one for you.
6. After installation you must modify the /etc/X11/
XF86Config file while logged in as root.
Look in the Device section and change the line
that says:
Driver "nv"
and change it to:
Driver "nvidia"
Look in the Module section and verify that you
have:
Load "glx"
You should remove the following lines (if they
exist):
Load "dri"
Load "GLcore"
Save and exit the XF86Config file.
7. Modify the /etc/security/console.perms file
and remove the line that starts with <dri>. This
is usually called:
<dri>=/dev/nvidia* /dev/3dfx*
Also remove the following line:
<xconsole> 0600 <dri> 0600 root
Save and exit the console.perms file.
8.Reset the permissions to the console.perms
file by typing in:
chmod 0666 /dev/nvidia*
chown root /dev/nvidia*
9. Reboot the PC and test the configuration by
starting the X Server (startx command) and running
an OpenGL application. If there are no problems
then modify the /etc/inittab file and change the
id:3:initdefault line back to id:5:initdefault.
You are now done. You will need to rerun the
Nvidia .run file everytime you update the kernel.