IIS PHP permissions

Hi I am trying to setup a intranet with IIS 5.1 and PHP 4.3.0 The problem I am having is that I want to retrieve all the usernames of the people on the network (aka DOMAIN\username) for security. I am using ISAPI to do this due to the CGI not retrieving the username. The problem I am having is that no user can login to the site for a php page unless they are a administrator but they can access ordanary .htm files etc without problem. I believe its permissions that are the problem and I was wondering if anyone could tell me how to set them up. Thanks From Shaun Garriock RGC Webmaster *** The contents of this message are confidential and are intended for the addressee only. The views expressed in this message do not necessarily represent those of Robert Gordon's College. Electronic mail transmission is not guaranteed to be secure, therefore, Robert Gordon's College does not accept liability for the contents of this transmission. This message does not form a legal binding contract. ***