Hi giovanni,
it could be that the eye tracker isn’t mounted as an active network interface. Try the command ifconfig -a to list the available interfaces. There should be one called usb0 or similar, and if you are lucky then there will also be a line starting with “inet addr” that shows the IP address bound to the interface. If not, you can try to activate the interface using the commands:
su
netcfg usb0 up
netcf usb0 dhcp