Kayako install - showing code on live response page?

We have had a Kayako install running fine for the last week, then all of a sudden when you click our live chat link, it opens a window that is blank.

We restart the server and now it shows code

Code:

//===============================
// Kayako LiveResponse
// Copyright (c) 2001-2011
// http://www.kayako.com
// License: http://www.kayako.com/license.txt
//===============================

var sessionid_cbf045fe = "997490d74fcd43a1b30ed59c49b6c70d";
var country_cbf045fe = "";
var countrycode_cbf045fe = "";
var hasnotes_cbf045fe = "";
var campaignid_cbf045fe = "";
var campaigntitle_cbf045fe = "";
var isfirsttime_cbf045fe = 1;
var timer_cbf045fe = 0;
var imagefetch_cbf045fe = 9;
var updateurl_cbf045fe = "";
var screenHeight = window.screen.availHeight;
var screenWidth = window.screen.availW
............

In IE it ask you to save the page index.php

We have tested PHP and it works fine, out PHP info page loads and shows everything clean, i even reinstalled PHP and such but no difference.

We are using IIS 6 with PHP 5.2.1

Any help on this?

Are you sure you have not made any changes to your server, make sure PHP is correctly loaded.

No changes made and PHP loads the phpinfo page fine.

the previous admin told me that once in a while it does this, the live chat window just wont load apparently and then it randomly fixes it's self.

There must be something deeper happening.

the live support client works, i can access the Kayako admin control panel fine, it is literally the only thing not working is the live response link.