I have disabled the web interface on the router and added port 80 forwards to 192.168.1.4 (Linux box) but it just doesn't forward.
I never knew that was possible to disable a router's web interface??? I would do not see the purpose of it? how would you be able to configure port forwarding???
How are you trying to access the website externally?
Do you have a website name already registered and reserved? or are you putting the external IP address in a web browser on a computer outside your network?