Mobilink web2sms

when ever i log on to web2sms mobilinkworld.com

then reply come

Dear User, If you are behind a firewall or within a company local area network (LAN), you will need to open outgoing TCP connections to Port 51215 on your proxy server.

i am using wirless modem no networking so please guide me in simple way thanx

Everywhere this topic on net... but no have given the right answer...... ANY GURU OF PAKISTAN CAN EXPLAIN WHT IS THIS AND HOW TO SOLVE THIS PROB>????

wireless modem but which connection?