observer not firing when saving product programatically

Question

I have 2 observers, catalog_product_prepare_save and catalog_product_save_after that work great when I save a product from admin or when a product is saved through a sale of the product. However they're not begin called from a script I wrote to update some data.

Script not calling observer:

$_product = Mage::getModel('catalog/product')->load($ProductID);
$_stockItem = $_product->getStockItem();

$_stockItem->setData('manage_stock', 1);
$_stockItem->setData('is_in_stock', 0);
$_stockItem->save();

$_product->setData($Attribute, $NewValue);
$_product->save();

My Observer xml file:

<?xml version="1.0" encoding="UTF-8"?>
<config>
    <modules>
        <Vampower_MyObserver>
            <version>0.0.1</version>
        </Vampower_MyObserver>
    </modules>

    <global>
        <models>
            <Vampower_MyObserver>
                <class>Vampower_MyObserver_Model</class>
            </Vampower_MyObserver>
        </models>

        <events>
            <catalog_product_prepare_save>
                <observers>
                    <Vampower_MyObserver>
                        <class>Vampower_MyObserver/observer</class>
                        <method>UpdateInfo</method>
                        <type>singleton</type>
                    </Vampower_MyObserver>
                </observers>
            </catalog_product_prepare_save>

            <catalog_product_save_after>
                <observers>
                    <Vampower_MyObserver>
                        <class>Vampower_MyObserver/observer</class>
                        <method>qtyUpdate</method>
                        <type>singleton</type>
                    </Vampower_MyObserver>
                </observers>
            </catalog_product_save_after>
        </events>
    </global>
</config>

Answer 1

in your root script add this

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

Answer 2

Solved the problem by switching the observer to catalog_product_save_before. Did not need to make any other changes to the code, everything worked perfectly.