Editing product link on shopping cart - "Cannot configure product"

Question

If I click the product edit link in the Shopping cart, follow message displays "Cannot configure product."

This message only displays if the product I am trying to edit is a configurable product.

Anyone got any ideas how to fix?

In the logs I am getting the following

exception 'Mage_Core_Exception' with message 'Mage registry key "old_skip_aleable_check" already exists' in /home/mydomain/public_html/staging/app/Mage.php:595
Stack trace:
#0 /home/mydomain/public_html/staging/app/Mage.php(223): Mage::throwException('Mage registry k...')
#1 /home/mydomain/public_html/staging/app/code/community/Easylife/Switcher/Model/Observer.php(58): Mage::register('old_skip_aleabl...', true)
#2 /home/mydomain/public_html/staging/app/code/core/Mage/Core/Model/App.php(1338): Easylife_Switcher_Model_Observer->checkShowStockOnConfigure(Object(Varien_Event_Observer))
#3 /home/mydomain/public_html/staging/app/code/core/Mage/Core/Model/App.php(1317): Mage_Core_Model_App->_callObserverMethod(Object(Easylife_Switcher_Model_Observer), 'checkShowStockO...', Object(Varien_Event_Observer))
#4 /home/mydomain/public_html/staging/app/Mage.php(448): Mage_Core_Model_App->dispatchEvent('controller_acti...', Array)
#5 /home/mydomain/public_html/staging/app/code/core/Mage/Core/Controller/Varien/Action.php(385): Mage::dispatchEvent('controller_acti...')
#6 /home/mydomain/public_html/staging/app/code/core/Mage/Catalog/Helper/Product/View.php(147): Mage_Core_Controller_Varien_Action->renderLayout()
#7 /home/mydomain/public_html/staging/app/code/core/Mage/Checkout/controllers/CartController.php(327): Mage_Catalog_Helper_Product_View->prepareAndRender('18269', Object(Mage_Checkout_CartController), Object(Varien_Object))
#8 /home/mydomain/public_html/staging/app/code/core/Mage/Core/Controller/Varien/Action.php(418): Mage_Checkout_CartController->configureAction()
#9 /home/mydomain/public_html/staging/app/code/core/Mage/Core/Controller/Varien/Router/Standard.php(250): Mage_Core_Controller_Varien_Action->dispatch('configure')
#10 /home/mydomain/public_html/staging/app/code/core/Mage/Core/Controller/Varien/Front.php(172): Mage_Core_Controller_Varien_Router_Standard->match(Object(Mage_Core_Controller_Request_Http))
#11 /home/mydomain/public_html/staging/app/code/core/Mage/Core/Model/App.php(354): Mage_Core_Controller_Varien_Front->dispatch()
#12 /home/mydomain/public_html/staging/app/Mage.php(684): Mage_Core_Model_App->run(Array)
#13 /home/mydomain/public_html/staging/index.php(87): Mage::run('', 'store')
#14 {main}

Answer 1

OK I found it.
I will release a new version on github today.
But you shouldn't wait until then. Here is what you need to do:

Edit app/code/community/Easylife/Switcher/etc/config.xml and remove this section from inside the <events> tag.

        <controller_action_layout_render_before_checkout_cart_configure>
            <observers>
                <easylife_switcher>
                    <class>easylife_switcher/observer</class>
                    <method>checkShowStockOnConfigure</method>
                </easylife_switcher>
            </observers>
        </controller_action_layout_render_before_checkout_cart_configure>

Clear the cache and it should work.