I've experienced similar problems backing up a Windows 2000 client
(with the Cygwin Amanda client) from a Red Hat Enterprise Linux 2.1 AS
(Itanium) box.  The errors only happen when the Windows box is on the
far side of a Fedora Core 2 bridge/gateway.  When the Windows box is
directly attached to the same network as the Amanda server, it works
fine.  Oddly enough, the Fedora Core 2 box that I back up in the same
configuration also works fine.

Fortunatly, I have a plentiful supply of kernel hackers here, so if
I get good tcpdump output(s) from tonight's run, maybe I can find out
what's happening.

                        -- JF