Need help calling PHP page from another server.

I am using a chat program and trying to call the status page from another server and the graphic that the page returns does not show up. It works if you are calling from the webserver that the chat program is working so i feel it is some type of config problem or security issue. http://www.hidho.com/chattest.htm is the page that uses the code <a href="javascript:pophelp(' http://chat.siuprem.com/siupchat/client.php',500,500)"><img src=" http://chat.siuprem.com/siupchat/statusimage.php"></a> and it works on http://chat.siuprem.com/siupchat/chattest.htm which is the windows IIS sesrver where PHP is running. Any help would be great. /Robert