RTL8139 boot problems

Hello,

I'm running RedHat 8.0 on a Athlon 1.8Ghz box that has two Realtek NICs, one 
'B" revision the other a "C" revision. The cards have been in place for well 
over a year w/o problems. 

After an upgrade to RH8 with kernel 2.4.18-14, the cards continue to function 
w/o problems, but when I attempt to compile a newer kernel, the message:

ifup: 8139too device does not seem to be present, delayi
Feb  5 10:05:39 localhost network: Bringing up interface eth0:  failed

appears, and neither card is seen. I've tried compiling the 8139 as a module 
and built-in - both fail. Have I missed some compile option or something? I'm 
scratching my head over this one. 

Thanks,

Jeff Elkins