Procedure Or Function '' Has Too Many Arguments Specified.

Im getting this error when looping through a gridview. Im trying to save each row into the database. The weird thing is that it saves the first row, but errors out on the second.
If I only add one item to the gridview, it works. The second row is screwing it up somehow. 
Any ideas?

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Some of my code to get an idea of how im doing it:
(This
is for a shopping cart. It displays the products in the shopping cart.
If the order is approved by the CC processing company, each product
entry is saved in the DB. The gridview is being populated by my
ShoppingCart Profile Object.)
 
  SqlConnection objConn = new SqlConnection(ConfigurationManager.ConnectionStrings["rdevie"].ConnectionString);
SqlCommand objCmd = new SqlCommand("InsertOrderDetails", objConn);
objCmd.CommandType = CommandType.StoredProcedure;

objConn.Open();

foreach (GridViewRow row in gvOrderDetails.Rows)
{
objCmd.Parameters.Add("@idOrder", SqlDbType.Int).Value = orderNum;
objCmd.Parameters.Add("@fldName", SqlDbType.NVarChar).Value = ((Label)row.FindControl("lblName")).Text;
objCmd.Parameters.Add("@fldUnitPrice", SqlDbType.Money).Value = ((Label)row.FindControl("lblUnitPrice")).Text;
objCmd.Parameters.Add("@fldQuantity", SqlDbType.Int).Value = Convert.ToInt32(((Label)row.FindControl("lblQuantity")).Text);
if (!String.IsNullOrEmpty(((Label)row.FindControl("lblSku")).Text))
objCmd.Parameters.Add("@fldSku", SqlDbType.NVarChar).Value = ((Label)row.FindControl("lblSku")).Text;
else
objCmd.Parameters.Add("@fldSku", SqlDbType.NVarChar).Value = DBNull.Value;
objCmd.Parameters.Add("@fldSize", SqlDbType.NVarChar).Value = ((Label)row.FindControl("lblSize")).Text;
objCmd.Parameters.Add("@fldLogo", SqlDbType.NVarChar).Value = ((Label)row.FindControl("lblLogo")).Text;
objCmd.Parameters.Add("@fldPlacement", SqlDbType.NVarChar).Value = ((Label)row.FindControl("lblPlacement")).Text;
objCmd.Parameters.Add("@fldColor", SqlDbType.NVarChar).Value = ((Label)row.FindControl("lblColor")).Text;

objCmd.ExecuteNonQuery();
}

objCmd.Dispose();
objConn.Close();
objConn.Dispose();