Port forwarding just wont work

hi guys,

trying to setup port forwarding so i can view my cameras on my dvr over the internet, internally its working fine...
i have the port opened on the firewall of my router to its correct (the DVR) ip address 192.168.1.127
i cant rdp into another computer either
i have tried two different routers with the same result (one is brand new, that come from the isp)
its like the rules are just not working
i phoned my isp who said that they dont offer support for port forwarding!!!
When i use shields up or a similar port scanning website it says no ports are opened
where can i start looking to resolve this problem?
any info appreciated...