a webbroadcast problem in actiontec's R1524 dsl modem

Dear advanced linux users:

I can see the public ip from status(a modem setup page 192.168.0.1,
but after I launch apache webserver , why when I type in
http://(publicip), I can not see my test page? I ever call actiontec
tech support, he said change it to port different than 80 in my
web.conf, and adding port forwarding to include that port(tcp, I
assume), but it still not work.
please help on this

sincere eric