Session to Int to SQL Error

I am trying to grab the session variable which is a number and use it in my SQL stmt.  It's adding the info to the DB but it throwing an error in my literal.

Here is the code and error:

        int myValue = Convert.ToInt16(Session["UniqueOrder"]);

        addAdapter.InsertPurchaseOrderItem
        (
            myValue,
            Convert.ToDecimal(txtUnitPrice.Text),
            Convert.ToInt32(txtQuantity.Text),
            txtAccountNumber.Text,
            txtProgramNumber.Text,
        & ...