Hang on, wait a minute, back up.
Linux filesystems are case-sensitive. When I said libGL, I meant libGL. Not libGl. That's a different file, and actually, it shouldn't exist.
Try getting rid of anything that starts with libGl.
Then try uninstalling the NVIDIA_GLX package, and reinstall it from tarball.
Then, do a find /usr -name 'libGL*' and post what it prints (it'll probably take a while to churn through your /usr directory, though). You may have to move some files manually if they exist in strange places where the driver won't move them for you.
Also, right after installing NVIDIA_GLX, do the ls -l /usr/lib/libGL* again, and make sure the right files are there, pointing to the right places (anything pointing at /usr/X11R6/anything is very likely wrong, unless it's libGLU).