gaah! dapper upgrade on server --> lost ethernet!

[matt.price at utoronto.ca]

Hi,

I run a small web server which I've just upgraded to dapper.  everything works
fine exceptthat the NIC no longer works!  ach!  lspci shows a realtek 8139c. 
lsmod shows the 8139cp and 8139too modules are loaded.  However ifup eth0 gives 

SIOSCIFADDR: no such device. 
eth0: ERROR while getting interfacde flags: no such device

I'm at a bit of a loss -- Actually I have 2 nics on this machine, not sure which
one isn't being seen, but have tried numerous timeswith both and had no luck. 
What do I do next?  
I really appreciate help on this -- I am in dire straits!

thanks,

matt