Comment 4 for bug 96753

/etc/ethertypes (provided by ebtables) is not relevant to this; fixing that message doesn't fix the fault.

The problem appears to trigger for unconfigured interfaces; I have an eth0 that is not configured at boot time (no cable plugged in to the UTP socket), and 'scapy -h' (which should print out only the usage information, another issue in itself) fails as described. Give the interface an address ('sudo ifconfig eth0 10.10.10.10'), and 'scapy -h' works as desired.

scapy reads /proc/net/route for the interface list, and then tries to gather data about each one. It consults the Flags field, and will continue if the RTF_UP flag is set - this is supposed to represent a state of "route useable" from net/route.h

I'll do some more investigation after the next reboot :-)