The only ones I had a problem with are the kernel ones. I found out the hard way that when I updated the kernel, I also needed to update the nividia drivers. If Nvidia did not make any rpm's for the new kernel, I had to build them from source. To do that you also need the kernel source from RH which was not installed by default from the RHN. I went to RHN with Mozilla and it was not to hard to find the kernel source. Just make sure you download the same kernel source for the kernel you are running, the numbers need to match.