dynamic tables with Ajax

[stmHoyas]

I have a dynamic table in c# 2.0. The page has a Buton that add new row
in the database.
I try add this row in my Html Table witch Ajax method, but raise an
ComPlusExceptioncode. An example of this code is:

[Ajax.AjaxMethod(HttpSessionStateRequirement.Read)]
public void cargarUtillajesAjax() {
string insert = "insert into OFERTAS_UTILLAJES(id_oferta,tipo) values
(" + Session["id_oferta"] + ",1)";
FachadeClass.ejectSqlComand(insert);
TableRow rr=new TableRow();
TableCell cc=new TableCell();
cc.ID="myCell";
cc.Text="My text";
rr.Cells.Add(cc);
rr.ID="myrow";
tablaProt.Rows.Add(rr); //tableProt is the table when I want add the
new row.

The exception is raise on line "tableProt.Rows.Add(rr)". I want add
rows without reload the page. Exits other form??

Thanks, Iván.