svn: Checksum mismatch while updating

I keep on getting this error:

svn: Checksum mismatch while updating 'interfaces.lookup'; expected:
'2c21f93c8639901a28056a507aa54deb', actual:
'97c86da543f396d636e960e46dec7280'

on the same file over and over again. I've blown away my working copy
of the repo and re-checked out and the problem goes away for a while
and then returns.

Trying to understand two things:

1. What causes this and how I can prevent it from happening in the future?

2. Is there an easier way then blowing away my WC and re-checking out to fix it?

Thanks!

-- 
Aaron Turner
http://synfin.net/         Twitter: @synfinatic
http://tcpreplay.synfin.net/ - Pcap editing and replay tools for Unix & Windows
Those who would give up essential Liberty, to purchase a little temporary
Safety, deserve neither Liberty nor Safety.
    -- Benjamin Franklin
"carpe diem quam minimum credula postero"