Question : Connection refused with RealVNC/Tight VNC

Hi!, i got a serious problem that i can't get rid of.  I got a client with 7 computers connected to Internet via a Router. I log in the router to forward some ports to the different computers so that i can get into the computer with VNC/TightVNC. That way, when i enter a no-ip address with the port number to get the computer that i want. Example : myno-ip.info:5900 would go to the computer where i set up vnc server to accpet connections on port 5900 wich is the default one.

Right now, it works on 3 computers, so i have the four other ones wich won't work and i don't know why.  The right port has been open on the XP firewall and on the router but for some computers it just won't work. I get unable to connect to host: connection refused (10061)

the only common thing i would see would be the norton anti-virus, but for some computer with nav installed it work anyway. i'm out of ideas right now.

the example was for one of my client but it's not the only one where i have the problem

Answer : Connection refused with RealVNC/Tight VNC

Wouldnt mind some of those points,

Cheers,
Phil