>Will the upgrade fix our problem?

Yes, because you will then be able to assimilate the new peers files.

>Is there another possible answer, like somehow tracing the route of our
>distribution to see if it's bogged somewhere up or down the line?

No.  The problem is inherent in 1.8c, post-Y2K.

I don't mean to be a PITA, but we've been telling people that 1.8c was
not Y2K-compliant since early in 1999.  There are no fixes short of
upgrading to 1.8d.

Nathan