FTP connections denied: local IP

Since I'm behind a Debian 3.1 router, on every ftp site I log on, it disconnect me with: I won't open a connection to 192.168.1.x. I must be missing a rule in my iptables.

My default iptables rules:

iptables -A INPUT -i lo -j ACCEPT
iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -A INPUT -m state --state NEW -i ! eth0 -j ACCEPT
iptables -A FORWARD -i eth0 -o eth1 -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -A FORWARD -i eth1 -o eth0 -j ACCEPT
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
iptables -A FORWARD -i eth0 -o eth0 -j REJECT

Any clue?