Dynamically creating controls in table rows on click of a button

Hi,
I am trying to add a table row with two dynamic controls on a button click event -
1. DropDownList
2. Ajax Rating Control
 
I have succeeded to some extent. Generated the table row and cells and also added the dynamic DropDownList(DDL) and Ajax rating control inside the cells.
First problem when I click ajax rating control it is giving error "An unhandled exception has occoured:\r\n The Target control_id_rating for the callback could not be found or did not implement ICallbackEventHandler
I have tried to place it in update panel but in vein.
And here user can add as many rows with ddl and ajax rating so I am creating all the rows again as per the click counter.
here is the code:
protected void btnAdd_Click(object sender, EventArgs e) { int p = Convert.ToInt32(Session["count"]), i,j; for (j = ...