[CentOS] Yum broken after x86_64 upgrade

Sun Aug 15 23:09:13 UTC 2010
listmail <listmail at entertech.com>

Hi All,

I just upgraded a machine from CentOS 5.3 32-bit to CentOS 5.5 x86_64 using
the updater on the release disk. Now that the machine is running 64-bit, I
notice that Yum is broken, failing with the following error:
~~~
There was a problem importing one of the Python modules
required to run yum. The error leading to this problem was:
   /usr/lib/python2.4/site-packages/rpm/_rpmmodule.so: wrong ELF class: ELFCLASS32
~~~

OK, so I thought I could fix this by installing the dependency. After digging
through a bunch of cascading dependencies using rpm, I got to the elfutils,
which didn't want to install until I used the --ignorearch switch on rpm.
However, when I try to install the 64-bit version of rpm-libs on top of that,
I still get the complaint about the failed dependency on elfutils.

My first question is: Would I be better off just wiping the machine and
installing from scratch at this point, or is there some sane way to get yum
reconstructed?

And the second question: did I make a mistake by assuming that the upgrade
system would work as it should, or is this just a bug in the upgrade system?
And to my first question, does anyone know what else the updater is likely to
have broken? 

Thanks,
--Bill