readonly fields becomes editable in form's error

I am using the workaround posted in the form to make 2 text input fields in my form a readonly input and it works just fine, just notice that these 2 readonly fields becomes editable after the form is submitted with some missing or wrong data!!!!
I tested it over 10 times, the fields are NOT editable as long as the form isn't yet submitted, left some fields blank and submitted, the error messages appeared, and, bingo! the 2 readonly fields are now editable!!!!
What's wrong with this??

Aha, disabled ajax and it worked OK, anyway to go around this problem and keep ajax??
I want ajax=true to avoid duplicate submit by disabling the submit button once clicked, ajax=true do this by default, if there's any workaround/filter to disable the submit button once clicked without ajax=true gonna be great and just what I am after, its an order form and a duplicate orders gonna be a lot of pain later...

Thanks David
I've added it but its not working :(
While re-enabled ajax, ajax=true, In my head section I've the following code

jQuery(document).bind('gform_page_loaded', function(input, 2, 1){
});

Where "2" is my form ID, and "1" is page one of my form (my isn't a multi-pages form, so assumed 1 is the right integer, however, I tried it with "0" as well and didn't worked too)
What's wrong? what may I apply wrongly here??

Hi Muhammed, Could you paste a link to your website?

Hey guys, any reply here?? a week with no answer!