Since you did not mention anything about the disk, I take it that the install disk works and the network driver is detected. You need to create the installation tree and export it.
Copy all of the contents of the first 3 CDs, not just the RedHat folder. At least, that's what I did.
mkdir 775 /RedHat
cp /mnt/cdrom/* /RedHat -R
Repeat for disks 2 and 3.
You also need an entry in your /etc/exports file. A simple entry is:
Once, you have done that, activate the NFS services and make sure that it is booted with the machine. Go to another machine and make sure that the /RedHat share is mountable and readable.
Your next step should be to try a regular unkickstarted
NFS install to see if it works correctly. You can check what is wrong by going to the 3rd and 4th console during the install. (Alt + F3 / Alt + F4). These two screens should be especially helpful when trying to find out what went wrong. If nothing goes wrong, then try the kickstarted NFS install.