VNC with a router SMC ( SMC7004ABR )

[Mathieu St-Arnaud]

Hi,
I install VNC on my computer. With my SMC router ( SMC7004ABR ), I make the 
way to my computer.
I try to use VNC with Http://IP:5800, it's work but when I type the password 
and I press OK, 1 minute after, a message come:
"java.net.NoRouteToHostException: Operation timed out"

I think I have to put the port on the firewall of my router....
but i am not enable.
The SMC router ask
- trigger port (i put 5800)
- type (for the trigger port) (TCP/UDP)
- public port (i put 5800)
- type (for the public port) (TCP/UDP)
But I can not put 5800 to the trigger and to the public port (the router 
write "set up error")
I don't know what is a trigger and a public port....
VNC have two ports?

help me.....
thanks
mathieu