Kernel panic following yum with missing /etc/fstab

Issue

• During a routine 'yum update' session on RHEL 5.9 to move to 5.11, it was noted that 'yum' reported a failure to find '/etc/fstab'. (The file was indeed later found to be absent).
• Following a reboot, the new kernel panic-ed. I booted into the previous kernel, repaired the missing 'fstab' and modified 'grub.conf' to continue to point to the previously valid, older kernel.
• I want to be able to upgrade to the newer kernel that would have been configured had nothing gone wrong.
• If I understand correctly, it should be possible to run 'mkinitrd' now that the 'fstab' is correctly installed.
• Please confirm this and please direct me to the steps that I need to perform.