Recently I tried to get ettercap MITM arp attack to work with my Intel wifi link 5100 AGN. The target was a Sony Vaio pc with an Atheros AR928X wireless card, and the gateway an (older) Apple Airport Extreme. Problem is, I got the "SEND L3 ERROR packet was not forwarded (libnet_write_raw_ipv4() message too long".

Target machine runs on Vista 32 bit, latest driver from Sony site.
Attack machine: Backtrack 4
Gateway: latest firmware (5.7 I think)

What could cause this problem? The most obvious reason for me would be the Apple airport, however does anyone know why it does not work in combination with an Airport Extreme? When I connected the target machine through an Ethernet cable, no problem occured.

What I should try: replace the gateway with another one: I'm gonna try that tonight.
Any other suggestions?