How do you add a user agent into a proxy server?

I am having trouble getting google earth pro to work. Now the google support (or lack of support) team, suggest that we need to a user agent into our proxy server. But no one in a team of 20+ IT staff have heard of using "user agents" with regards to proxy server. We are using a standard Microsoft proxy, behind a check point firewall and we know that the firewall is definatly not causing the problem.

What is a VPN?

VPN is (Virtual Private Network) were first used by companies to enable their employees to securely access internal systems such as email remotely (e.g. from home or while on business trips). Today they are increasingly being used for personal use by individuals to protect their privacy while online in public places (e.g. when using the wi-fi connection in a cafe) or in a country where the internet is censored / blocked (e.g. China, Saudi Arabia��).