I had the same problem as you. Everyone with the zd7000 series is having it with drivers newer than 4336 ( www.zd7000forums.com
The solution is to install the 4336 driver set. To do this you will need to have the source installed so the nvidia driver can build the installer for your kernel. The source should be available through redhats update app)
I just solved the problem on my machine last night running Mandrake with a 2.4.22 kernel. Install the source to the default source directory. I forget what that is exactly and I am not at my linux machine to check but if you run the NVIDIA_Installer.run with the switch --advanced-options ( check readme for correct syntax search the readme file for the term kernel-install and you will see it) You can then use the switch to point to your source or put the source in the default directory( I had to do this for some reason). The installer should work once it can find the kernel headers and you will have the old drivers running w/o any flicker.
If that fails then you can manually compile the driver for your kernel. The driver will work on any 2.4 kernel its just that since it is old the installer can not handle kernels that were compiled after april 03. I hope this help somewhat. I had very little idea what i was doing but I got it to work eventually.