Missing Common/Logger extension

 If one of the files hasn't copied over correctly you will see an error similar to this:

        "Fatal error: Class 'Mage_Wsacommon_Helper_Data' not found in /home/yourdomain/yoursubdomain/app/Mage.php on line 520"


        "Fatal error: Call to a member function toOptionArray() on a non-object in /home/yourdomain/yoursubdomain/app/code/core/Mage/Adminhtml/Block/System/Config/Form.php on line 385"

Copy all the extension zips over, including the common library if available and refresh cache.