Get information from internet for my game

hi. i have a problem in my unity project. in my project i want to conect to the internet and get some information from database as xml file and use that data in my game. i use www class for getting this data.

but when i build my game and test it ina number of pc's, some of them can'not connect to my website and get that information ! for conect to internet i'm using adsl and router. and all of the pc's connect to the router. but some of them can't get that xml file.

why?