yum (rhel-i386-server-5): Metadata file does not match checksum

Hello all,

I run RHEL5 and recently have run into a problem with yum.

# yum update
Loading "rhnplugin" plugin
rhel-i386-server-5        100% |=========================| 1.2 kB    00:00
primary.xml.gz            100% |=========================| 1.5 MB    00:00
Error: failed to retrieve repodata/primary.xml.gz from rhel-i386-server-5
error was [Errno -1] Metadata file does not match checksum
#

I've tried, 'yum clean all', 'yum clean metadata'. Neither of which 
fixed the problem. I've done extensive google searching but none of the 
solutions out there seemed to work for my problem. I'm at a complete 
loss as to how to resolve this and am not too familiar with the workings 
of yum (coming from a debian background). I would great appreciate any 
help and/or suggestions.

Thanks in advance.
Nick