Comment 11 for bug 60388

I had the same problem, for just about any Ubuntu version I tried (dapper, edgy, feisty) and a range of kernels (generic and custom). Also I used to have the same problem in Gentoo aswell.

The ibm-script I'm referring to can be found at the above link or, more exactly, here:
http://www-307.ibm.com/pc/support/site.wss/document.do?sitestyle=lenovo&lndocid=MIGR-67166

Try this if nothing else works for you. Beware that this may break you ethernet card, or your system, or both, or maybe the earth will explode. Uh, that'd be inconvenient. Don't blow up the earth, please.

# Remove module if it was loaded.
sudo modprobe -r e1000

# Re-load it ignoring invalid EEPROM checksum.
sudo modprobe e1000 eeprom_bad_csum_allow=1

# Run the ibm script on the respective interface; for me it was eth0.
sudo ./vidalia-eeprom-mod-script eth0

# Reboot.
sudo reboot