Adding custom option to a product programatically in custom module frontend controller? - magento-1.6

Question

i am trying to add product from frontend programatically following this link :
Magento: Adding new products programmatically
but i want to extend it to add custom options too to it .And i added the following code to it
$options = array();
$options[$sku] = array(
'title' => 'Option Title',
'type' => 'radio',
'is_require' => 1,
'sort_order' => 0,
'values' => array()
);
$options[$addvp['product']['sku']]['values'][] = array(
'title' => 'Option Value 1',
'price' => 0.00,
'price_type' => 'fixed',
'sku' => '',
'sort_order' => '1'
);
$options[$sku]['values'][] = array(
'title' => 'Option Value 2',
'price' => 89.00,
'price_type' => 'fixed',
'sku' => '',
'sort_order' => '1'
);
foreach($options as $sku => $option) {
$id = Mage::getModel('catalog/product')->getIdBySku($sku);
$product = Mage::getModel('catalog/product')->load($id);
if(!$product->getOptionsReadonly()) {
$product->setProductOptions(array($option));
$product->setCanSaveCustomOptions(true);
//$product->save();
}
}
but it prints this error instead of adding custom option to product.
SQLSTATE[23000]: Integrity constraint violation: 1452 Cannot add or update a child row: a foreign key constraint fails (`vendor`.`catalog_product_entity`, CONSTRAINT `FK_CAT_PRD_ENTT_ATTR_SET_ID_EAV_ATTR_SET_ATTR_SET_ID` FOREIGN KEY (`attribute_set_id`) REFERENCES `eav_attribute_set` (`attribute_set_id`) ON DEL)

Answer 1

http://www.fontis.com.au/blog/magento/add-product-custom-options
Note:
The above link did what i want it to do. But one thing to be kept in mind that you must add the custom option to a product already exists/saved.

Answer 2

I had a similar issue. Turned out that the auto-generated SKU was somehow invalid or not properly saved on the new product I created for testing. The product was not invalid, as it did save properly on the first go, but when I revisited the product via the CMS and tried to click "save and continue" it suddenly prompted me to enter a SKU. When I re-entered the auto-generated sku it worked!
So the short answer would be: Check that your product exists by that SKU number. If it does, re-check that the SKU is being saved properly.