Some people have reported success using r8168 driver with these sort of ethernet controllers. YMMV.
I have a copy of the r8168 driver if you'd like to try it -
http://www.comnetel.com/r8168 Download the version for your architecture then do the following:
cp r8168.ko /lib/modules/2.6.9-78.0.22.ELsmp/kernel/drivers/net/r8168.ko
depmod -a
Don't forget to replace "2.6.9-78.0.22.ELsmp" with your currently running kernel version (uname -r)
Now you can either reconfigure the server via the console or do:
db configuration setprop EthernetDriver1 r8168
signal-event post-upgrade
signal-event reboot
Lloyd