Comodo Firewall blocks realvnc and also quick vpn

I have a netbook with windows xp home. I just installed comodo firewall and this is the problem i have… i use quickvpn from cisco/linksys to vpn into my office network and usually i am able to use realvnc to access my office computers and also check some settigns on the router by typing the ip adresss…since i installed comodo firewall…i still can make the quickvpn conection but when i try to access the ip adress of the router i am not able to access or if i use the real vnc…i get a black screen… if i unistall comodo it will work without any problem…any idea what settings i have to change on comodo firewall for it to work

Thanks

Rafael Gottenger