// Load whatever product represents the item the customer will be
// paying for and create a line item for it.
$line_item = commerce_product_line_item_new($product, $quantity, $order->order_id);

// Save the line item to get its ID.
commerce_line_item_save($line_item);


//***this is the part that's not working. trying to set the field_notes field***
$line_item_wrapper = entity_metadata_wrapper('commerce_line_item', $line_item);
$line_item_wrapper->field_notes->set("Does this work??");


// Save the line item to get its ID.
commerce_line_item_save($line_item);

// Add the line item to the order using fago's rockin' wrapper.
$order_wrapper = entity_metadata_wrapper('commerce_order', $order);
$order_wrapper->commerce_line_items[] = $line_item;

// Save the order again to update its line item reference field.
commerce_order_save($order);