Magento Template error Call to a member function toHtml()

when facing the above error:

Magento Template error:
Fatal error: Call to a member function toHtml() on a non-object in \app\code\core\Mage\Core\Model\Layout.php on line 529

the solution that did work for me as described here:

 http://www.meetc3.com/blog/solving-call-to-a-member-function-tohtml-magento-error.html

Navigate to
\app\design\frontend\default\themename\layout\page.xml

Find

<block type="core/profiler" output="toHtml"/>

Replace with

<block type="core/profiler" output="toHtml" name="core_profiler"/>