I don't know what
VNC from the linux box onto my main box
means. Which box is running the vnc server and which box is running the viewer? Which box ran the netstat? Can the linux box view its own vncserver? Can the Windows box do that?
After playing around with the firewall
Don't "play around" with netfilter. Let some package like firestarter set it up for you and don't change anything you don't yet understand. Please show the output of
ps axw| grep -i vnc
iptables -L INPUT
iptables -L OUTPUT
iptables -L FORWARD
If more tables are mentioned in those tables, list them too.