CN5 error in uucp

[cpr at SU-SHASTA.ARPA]

Does anyone know what a
... FAILED (CN5)
error means when copying files to another machine?  The file madeit
over just fine, but ended up being stuck in ~uucp.  Sounds like a protection
bug, but all the directories involved are rwx to everyone, and USERFILE
lets anyone do anything to /usr/spool.  (This is sending from a 4.1a Berkeley
Unix system to a 4.2 Berkeley Unix system; we don't have sources, or I wouldn't
trouble you.)

Thanks.

--Chris Ryland