The problem is, that you are not allowed to save products from the frontend.
The origData property is not filled

public function setOrigData($key=null, $data=null)
{
    if (Mage::app()->getStore()->isAdmin()) {
        return parent::setOrigData($key, $data);
    }

    return $this;
}

So when you try to save the product, this error is raised.

What to do when you encounter this error ?

A quick fix is to add this before saving, on your controller for example.

Mage::app()->setCurrentStore(Mage_Core_Model_App::ADMIN_STORE_ID);

A proper solution is to extend Mage_Catalog_Model_Product and replace setOrigData method

public function setOrigData($key = null, $data = null)
{
    if (is_null($key)) {
        $this->_origData = $this->_data;
    } else {
        $this->_origData[$key] = $data;
    }
    return $this;
}

The post Magento app/code/core/Mage/Eav/Model/Entity/Abstract.php on line 1180 error appeared first on Agence de Développement Informatique du Nord.