Reason for $oHTTP.Send() to fail?

[DeLaRivaGuard]

I was trying out this small example:

$oHTTP = ObjCreate("winhttp.winhttprequest.5.1")

$oHTTP.Open("GET","http://www.AutoItScript.com")

$oHTTP.Send()

$HTMLSource = $oHTTP.Responsetext

However, I always receive following error, no matter what URL link is being used:

The requested action with this object has failed.:

$oHTTP.Send()

$oHTTP.Send()^ ERROR

Afaik, this example worked while trying it at home. Now that I'm trying this at my company, the above error is shown.

Can the corporate firewall be the reason?

Thanks in advance.