fnGetData return undefinited value for .json load

DotComWA

Hi, everyone!
From few days i've some problem with datatables jquery...what happened?

Ok, the trouble is little complex but i want to try to explain it.

I have an ecommerce with 1200 products, and some mysql data of these products are loaded in a json file every day because in this way loading time is much faster.

Well, datatables correctly load my products and i see all of them in my table. Now, i want to edit some fixed datas in every row (discount and price) but there's something wrong now because when i click on my edit button the function fnGetData seems give me an empty array, why?

How can fix them?

This is my code, I hope that someone could help me!

http://live.datatables.net/nevaqegu/2/edit?html,js,output

ps: in this case the products not loaded from json, why?

edit:
below the access to my webapp to see live what happened

username: aaaaa@aaaaa.it
password: 123456
link: www.mastergroupitaly.com/rivenditori/index.php?p=test