Etch: network won't work

["Robert S" <robert.spam.me.senseless@gmail.com>]

I have cloned my installation of Etch onto another (ancient PII) system for 
backup purposes.  When the network starts on the second system I get 
messages like this:

SIOCSIFADDR: No such device

.. and the network does not work (when I do 'ifconfig' I only get 'lo').  My 
network card is the same as on the original system - Realtek 
RTL-8139/8139C/8139C+.  The same modules are installed on both machines:

$ lsmod |grep 8139
8139cp                 20736  0
8139too                24192  0
mii                     5376  2 8139cp,8139too

If I boot from an old 2.4 kernel the network works OK (but certain other 
things don't)- so the hardware is OK.

Any clues?

--