'status' is null or not an object error

[secondstrade]

Have Installed all pre requisites. All green ticks. I have not created a db yet so chose the Advanced option.  Gave the UN and password and got into the next screen. Selected Country and NEXT. Wait goes on forever. Cannot proceed. Please advise.  

I have installed OS Class version 2.1.1 on Windows running on IIS v 5.1 MySQL v  5.0.45.

While Installation on Step 2 -3 either select 1 country or Worldwide - nothing happens, not progressing to the next step.

Error on page: is given below.

Webpage error details

User Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; .NET CLR 1.1.4322; .NET CLR 2.0.50727; .NET CLR 3.0.04506.30; .NET CLR 3.0.04506.648; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729; .NET4.0C; .NET4.0E)
Timestamp: Sun, 10 Jul 2011 06:11:53 UTC


Message: 'status' is null or not an object
Line: 94
Char: 13
Code: 0
URI: http://localhost/oc-includes/osclass/installer/install.js

Checked the code in install.js, ( if(data.status == 200))this part is having the problem. Code is attached below. Please advise.

$.ajax({
        type: 'POST',
        dataType: 'json',
        url: 'install-location.php',
        data: input,
        timeout: 600000,
        success: function(data) {
            if(data.status == 200) {
                window.location = 'install.php?step=4';
            } else {
                window.location = 'install.php?step=4&error_location=1';
            }
        },

Expecting your quick response on this. Thanks  

@Juan Ramon: I've locked this topic because it's duplicated.