Column filtering not working on multiple columns

Hello,

I have an issue with my datatables. All the data is put in a database and I'm using server-side processing. My issue is about column filtering. If I try to filter one column everything is working ok. If I try to filter another column, I don't get any results.

Here is a link http://stilbarbatesc.ro/ag2/test/

I used firebug to see what's up when filtering on the second column and on every search I get this

{"sEcho":80,"iTotalRecords":"4228","iTotalDisplayRecords":"5","aaData":[]}

The only thing that changes on the above line is the sEcho which has different values.

If there are needed certain files to be posted please tell me.