invalid method in /lib/Varien/Object.php after update, causing maintenance mode

Question

I just updated some modules and now my webshop keeps showing the maintenance page, whilst there is not maintenance.flag file in the root folder.

I checked the /var/log and in the exception.log it keeps showing this error:

2015-09-30T10:33:15+00:00 ERR (3): 
exception 'Varien_Exception' with message 'Invalid method Itoffshore_Products_Block_Price::callParentToHtml(Array
(
)
)' in /home/users/amanvftp/amanvida.eu/lib/Varien/Object.php:653
Stack trace:
#0 /home/users/amanvftp/amanvida.eu/app/code/core/Mage/Catalog/Block/Product/Abstract.php(398): Varien_Object->__call('callParentToHtm...', Array)
#1 /home/users/amanvftp/amanvida.eu/app/code/core/Mage/Catalog/Block/Product/Abstract.php(398): Itoffshore_Products_Block_Price->callParentToHtml()
#2 /home/users/amanvftp/amanvida.eu/app/design/frontend/default/aman-mobile/template/catalog/product/view.phtml(62): Mage_Catalog_Block_Product_Abstract->getTierPriceHtml()
#3 /home/users/amanvftp/amanvida.eu/app/code/core/Mage/Core/Block/Template.php(241): include('/home/users/ama...')
#4 /home/users/amanvftp/amanvida.eu/app/code/core/Mage/Core/Block/Template.php(272): Mage_Core_Block_Template->fetchView('frontend/defaul...')
#5 /home/users/amanvftp/amanvida.eu/app/code/core/Mage/Core/Block/Template.php(286): Mage_Core_Block_Template->renderView()
#6 /home/users/amanvftp/amanvida.eu/app/code/core/Mage/Core/Block/Abstract.php(919): Mage_Core_Block_Template->_toHtml()
#7 /home/users/amanvftp/amanvida.eu/app/code/core/Mage/Core/Block/Text/List.php(43): Mage_Core_Block_Abstract->toHtml()
#8 /home/users/amanvftp/amanvida.eu/app/code/core/Mage/Core/Block/Abstract.php(919): Mage_Core_Block_Text_List->_toHtml()
#9 /home/users/amanvftp/amanvida.eu/app/code/core/Mage/Core/Block/Abstract.php(637): Mage_Core_Block_Abstract->toHtml()
#10 /home/users/amanvftp/amanvida.eu/app/code/core/Mage/Core/Block/Abstract.php(581): Mage_Core_Block_Abstract->_getChildHtml('content', true)
#11 /home/users/amanvftp/amanvida.eu/app/design/frontend/default/aman-mobile/template/page/1column.phtml(59): Mage_Core_Block_Abstract->getChildHtml('content')
#12 /home/users/amanvftp/amanvida.eu/app/code/core/Mage/Core/Block/Template.php(241): include('/home/users/ama...')
#13 /home/users/amanvftp/amanvida.eu/app/code/core/Mage/Core/Block/Template.php(272): Mage_Core_Block_Template->fetchView('frontend/defaul...')
#14 /home/users/amanvftp/amanvida.eu/app/code/core/Mage/Core/Block/Template.php(286): Mage_Core_Block_Template->renderView()
#15 /home/users/amanvftp/amanvida.eu/app/code/core/Mage/Core/Block/Abstract.php(919): Mage_Core_Block_Template->_toHtml()
#16 /home/users/amanvftp/amanvida.eu/app/code/core/Mage/Core/Model/Layout.php(555): Mage_Core_Block_Abstract->toHtml()
#17 /home/users/amanvftp/amanvida.eu/app/code/core/Mage/Core/Controller/Varien/Action.php(390): Mage_Core_Model_Layout->getOutput()
#18 /home/users/amanvftp/amanvida.eu/app/code/core/Mage/Catalog/Helper/Product/View.php(147): Mage_Core_Controller_Varien_Action->renderLayout()
#19 /home/users/amanvftp/amanvida.eu/app/code/core/Mage/Catalog/controllers/ProductController.php(132): Mage_Catalog_Helper_Product_View->prepareAndRender(332, Object(Mage_Catalog_ProductController), Object(Varien_Object))
#20 /home/users/amanvftp/amanvida.eu/app/code/core/Mage/Core/Controller/Varien/Action.php(418): Mage_Catalog_ProductController->viewAction()
#21 /home/users/amanvftp/amanvida.eu/app/code/core/Mage/Core/Controller/Varien/Router/Standard.php(254): Mage_Core_Controller_Varien_Action->dispatch('view')
#22 /home/users/amanvftp/amanvida.eu/app/code/core/Mage/Core/Controller/Varien/Front.php(172): Mage_Core_Controller_Varien_Router_Standard->match(Object(Mage_Core_Controller_Request_Http))
#23 /home/users/amanvftp/amanvida.eu/app/code/core/Mage/Core/Model/App.php(365): Mage_Core_Controller_Varien_Front->dispatch()
#24 /home/users/amanvftp/amanvida.eu/app/Mage.php(684): Mage_Core_Model_App->run(Array)
#25 /home/users/amanvftp/amanvida.eu/index.php(94): Mage::run('', 'store')
#26 {main}

When I check the Object.php file I indeed notice that the callParentToHTML method does not exist. And according to the documentation, it shouldn't exist.

http://doc-magento.com/nav.html?lib/Varien/Object.php.source.html

1. How do I resolve this issue?
2. Is this the reason why my site is showing the maintenance page or should I dig deeper? And how would I troubleshoot the issue that is causing this. (Funny thing is the maintenance page is only showing for the product pages and cart, not for homepage and category pages.)

Answer 1

it seams you have an extension called Itoffshore_Products containing this block Itoffshore_Products_Block_Price and this block does not contain the method callParentToHtml.
The first thing you can try is to add this in the block mentioned above

protected function callParentToHtml()
{
    return $this->toHtml();
}

Clear the cache and see what happens.
If that doesn't work, contact the extension developer for support.