There seems to be an issue with the network driver for the Dell Optiplex 760 and Suse 11.2 This problem resides in the e1000e driver that is supposed to superceede the e1000 driver. What needs to be done is blacklist the e1000e driver and revert back to the e1000 driver that does work with this network card.
Edit the File /etc/modprobe.d/50-blacklist.conf
Add a the line to the bottom of the file
blacklist e1000e
Then still as root run these commands
#rmmod e1000e
#modprobe e1000
#rcnetwork restart
should only show on module loaded.
#lsmod | grep -i e1000
If it shows multiple then reboot, you should be able to configure the network card via Yast2 now.