If you put your PC in the WNR2000's DMZ (and have the application running on the PC), is application still not visible to the Internet?
Having the application running (and not having the PC's firewall blocking access) is as important as the DMZ and/or port forwarding in the NAT router.
If your WNR2000 is similar in function to my WNR1000, I found that if I have Remote Management enabled (no matter what port is used), the WNR1000 will not forward port 80, or pass it through to the DMZ. I have found that my WNR1000 also blocks port 123 regardless of DMZ and/or port forwarding. I have also run into other routers that would (seemingly) arbitrarily block DMZ and port forwarding for specific ports such as 1080 and 8080.--
We can never have enough of nature.
We need to witness our own limits transgressed, and some life pasturing freely where we never wander.