I edited my interfaces to be like the one SoundSquare provided. I changed the entry under Domain names in the Xubuntu network configuration tool to be my router (it looked like it may have been set to some other router).
Unfortunately, still no luck. When I run usr/sbin/ifconfig it gives me some text starting with:
Link encap: Local Loopback
inet addr: 127.0.0.1 Subnet mask: 255.0.0.0
inet 6 addr: 1/128 Scope = host
UP LOOPBACK RUNNINING MTU:16436 Metric 1
And then zeros for RX Packets, TX packets and everything else.
Perhaps it is compound problem with the Efika hardware not liking my Linksys router or vice versa. Not sure what else to try except perhaps adding my router's IP under Hosts in the network configuration tool or plugging in static values on the Efika instead of selecting DHCP.
I did not install from the network. The machine came preinstalled.
Also noticed a user describing similar problems at ubuntuforums.org:
http://ubuntuforums.org/showthread.php?t=592111.