problem from local machine

I posted the same problem before but no luck i'm just gonna reword ..

Greeting all,
I have a weired problem, here is the scenario:
- i have a router with firewall enabled, Port 80 is open.
- I'm hosting 2 web sites from a dsl connection (i have a static ip) which works perfect if you try to access it from any where (global) , but when i try to access the web from any local computer, the page doesn't come on(page can't be displayed) . Even if i type the ip address in the browswer, If i ping the web, it replies with the correct ip.
- Also same problem occures when i'm checking or sending my email from a local machine, (using my global ip address or using my name server (eg mail.mydomain.com)

- I'm using an externel DNS server

Here is another thing i changed the router (from compaq Ipaq to Dlink 704) and the Dlink router works no problem, but using the compaq router, give me the above problem.

I doupt it is a DNS problem , there must be something about the router, but i really give up, and don't know how i could access the web locally,

Any help or resources will be greatly appreciated,

Thanks for any input or ideas,
Max