Chiara threw another network hissy fit. Dmesg was spammed with a bunch of messages like eth0: link up appearing rapidly.
eth0: link up
Some googling indicated that this error message in conjuction with the very ethernet board and driver that Chiara had in use could be solved by updating with an appropriate driver from the manufacturer.
In essence, I followed steps 1-7 from here: http://ubuntuforums.org/showthread.php?t=1661489
So far, so good. We'll keep an eye out to see how it works...