The IBM ServeRAID 4(M/L) Adapter is not supported during installation. This makes it impossible to install RH Linux on any server using the IBM serveRAID 4(M/L) adapter for the root/boot disk. (SuSE, Caldera, and even Turbo have already released updated install diskette images, hopefully Red Hat will soon)
Could you please give the output of 'lspci' and 'lspci -n' commands on this system?
Please reopen this problem if you continue to have problems.