I'm not sure whether this is worth pursuing, but we just rediscovered
for ourselves the same things that were discussed last year in
reference to SL302, under the Subject: header "Re: openafs on SL302".

First we misguidedly tried "yum install openafs"

Then we found we couldn't remove it:

rpm -e openafs
  error: %preun(openafs- ...  ) scriptlet failed, exit

Then we remembered that, to do what we wanted, we *should* be using

yum groupinstall "OpenAFS Client"

But that failed:

 ....Unable to satisfy dependencies
 Package kernel-module-openafs-2.4.21-20.EL needs
 /boot/vmlinuz-2.4.21-20.EL, this is not available.

Evidently, that's because we've been through several kernel version
updates since then, and we had deleted the older kernels.

As soon as a successful installation had been achieved, the next
updates would have made that particular dependency pointless.  But it
seems it's needed or else one can't get started.

We considered either (1) re-installing the original kernel in the hope
that it would allow the installation of openafs client to proceed in
the way that it's evidently meant to work; or (2) using rpm to
manually install the latest versions of the needed openafs components,
then running yum to verify that it was happy with the result.

We chose the latter.  It succeeded.  (I.e after we had configured the
default cell, and started the afs service with /etc/init.d/afs start).

I don't understand enough about the details of the yum procedure to
make a detailed technical proposal for improvement; but anyway, this
note might just help some other user.

thanks