Perhaps the X settings you have are incompatible with the framebuffer settings UT is trying??
I've got LM9 and the texstar NVIDIA-rpms, all is going well.
Just downloaded the UT2003-demo and started it. Then i init3 and turned on 'X &' with a following 'export DISPLAY=":0" ', telling him where to find X....
I did that, to prevent my system beeing something slower because of a windowmanager
Try it that way, then you'll find out, what he did in "/var/logs/xfree4.0.log".
Perhaps he's initialising 16Bit colordepth and you run UT with 32?!