Looks like you need to modprobe NVdriver as root before you startx.
You can automate this by (let's see... RH 7.2...) adding an alias to /etc/modules.conf, but the alias depends on what's in your /dev directory. If almost everything in /dev shows up in yellow, making them all devices (I believe the color scheme for ls is the same in RH as it was in Mandrake...), then you need to make sure there are files in there named nvidiactl, nvidia0, nvidia1, nvidia2, and nvidia3. Then add a line to /etc/modules.conf looking like this:
alias char-major-195 NVdriver
If, on the other hand, almost everything in /dev is a symlink (shows up in cyan/light blue), then your alias line should look like this:
alias /dev/nvidia* NVdriver
After you've made the change, it should work after a reboot. If you just manually modprobe NVdriver, then it'll work only until you reboot.