Arpspoofing Problem

Dear all,

I've got some problems with arpspoofing,

Situation.
Host Machine MACbook , guest backtrack 5r3.
Connected via bridge , while i try to arpspoof a host machine thats connected to the same network.. The internet dies on the spoofed machine!

I'm using VM fusion to run backtrack!

What do you think is causing the problem? It's been a hustle, ive been trying to fix it for a month now!
Whenever i try to arpspoof a victim, the internet goes dead! on the victim!

I would document myself more in the actual background process of what you are trying to do. Once you understand the background it will be easier to troubleshoot.

Whenever i try to dns_spoof or arp spoof the network, the target machine looses internet connection. (Target machine is a OSX) - Router used (WAG320N).

hmm.. i was thinking.. does the OSX have poisioning protection by default or something? or maybe the linksys router i'm using has some settings that prevents the arp poisioning?

This is giving me a headache.... anyone??