Store not working after successful SUPEE-6788_CE_1.9.2.1 patch

[szhmg]

I have two magento stores that has the following error after a successful SUPEE-6788_CE_1.9.2.1 patch. 

Fatal error: Class 'Varien_Data_Collection_Db' not found in /home/xxx/public_html/catalog/app/code/core/Mage/Core/Model/Resource/Db/Collection/Abstract.php on line 36

Line 36 of that file is as follows:

abstract class Mage_Core_Model_Resource_Db_Collection_Abstract extends Varien_Data_Collection_Db
{
const CACHE_TAG = 'COLLECTION_DATA';

My store was running 1.9.2.1 before the patch.

Any help is greatly appreciated.

[szhmg · Accepted solution]

I found out it was a file ownership problem as I used the root account to patch. Just need to change the file ownership.