I run Gentoo linux, and consistent NIC naming has been introduced since udev v197 I think. So activation was an issue for me as I had no eth0 device on my system.
My work-around was to create a udev rule to force the name eth0.
I have the following in /etc/udev/rules.d/70-use-eth0-for-matlab-licensing.rules (one line):
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="your:mac:address:here", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="eth?", NAME="eth0"
You can find the mac address of your device by running 'ifconfig -a'. Keep it in lower-case. I used my ethernet NIC's mac, as I hardly use it, so I'm hoping this won't have unintended consequences for the rest of my system.
You'll need to keep this work-around for as long as you use matlab (not just for activation), as the licensing info is verified at launch, so it needs to find eth0 every time.
You may have to update a /etc/init.d/net.* link and /etc/conf.d/net to use the new name.