I have no problem with installation, however MITM doesn't work.

When I invoke script, I can see both ettercap and password terminal window running.

Victim (me) is running Windows 7.
arp -a shows that victim is using spoofed (N900) gateway.

I cannot browse internet on victim machine, (or at least it's to laggy). SSLStrip is not working (tried on facebook).

When I invoke iptables --list on N900 there are no rules.