Changed files overwritten with old version upon commit

I have a strange scenario:
We are two developers that use an SVN repository to coordinate code
releases.
I pull down the repository daily, often several times a day.  I recently
committed to the server and it "blew away" my coworkerıs changes, without
any sort of conflict.  Like not a few lines of code, but a hundred or so.
This has happened twice now on two separate occasions both recent.

Here's the catch: I actually saw in my local dev some of the code that got
blown away by my most recent commit.  So the code must have been in my local
repository prior to committing.  Any way to check this? Local logs or
anything?

I am using version 1.6.5 and the svn server is on Unfuddle.

Any ideas how or why it would have overwritten the file with an older
version upon committing?

Also, any ideas where the problem may lay: my svn client, coworker's svn
client, or Unfuddle?

I'm happy to provide any additional details anyone thinks may be helpful.

MUCH thanks in advance,
Steve Calamia
Received on 2010-03-16 19:30:08 CET