My second note elicited a ton of replies. Thanks everyone! I took the easiest suggestion, which was plugging the SCSI hardware into the slower SCSI channel and the result was a successful copy of gobs of files from one machine to another. Instead of the constant throb of orange collision lights on my hub, the collisions were fewer, intermittent, and didn't bother the Debian system at all. No I/O error messages were logged in /var/log/messages. Recompiling Kernels is a little beyond my abilities right now, so this fix should suffice for the short term. Thanks again.
-- Jamie Hutt Basement dweller, huttstuff.com