GLX problem gone
I appreciate the feedback. I don't know what went wrong the first time, but glx is now working after a second installation.
In /usr/X11R6/lib/modules/extensions/ there is no libglx.a, only the symlink libglx.so to libglx.so.1.0.4363 and libglx.so.1.0.4363 itself. I didn't have a chance to check for libglx.a before the reinstallation of 4363.
The only difference I can think of between these two installations of 4363 is that the first time I used nvidia-installer --update and the second time I had downloaded and then ran NVIDIA-Linux-x86-1.0-4363.run.
It may therefore be that running nvidia-installer --update causes the problem.
Cf. the separte thread on RH9 and GLX failing to load.