Problem is here:
SqlDataAdapter AD = new SqlDataAdapter(insertStatement, myConn);
replace it with:
SqlDataAdapter AD = new SqlDataAdapter(sqlCommand);
and also you are using this overload i think:
AD.Fill(DS, "NameOfDataTable");
then you can access it like this:
DataTable DT = DS.Tables["NameOfDataTable"];
insetad of using 0 index.