Mage registry key "_singleton/Satvacart_FacebookCAPIIntegration_Model_Observer" already exists

#0 /Data/satvacart.com/public_html/app/Mage.php(223): Mage::throwException('Mage registry k...')
#1 /Data/satvacart.com/public_html/app/Mage.php(477): Mage::register('_singleton/Satv...', false)
#2 /Data/satvacart.com/public_html/app/code/core/Mage/Core/Model/App.php(1316): Mage::getSingleton('Satvacart_Faceb...')
#3 /Data/satvacart.com/public_html/app/Mage.php(448): Mage_Core_Model_App->dispatchEvent('controller_acti...', Array)
#4 /Data/satvacart.com/public_html/app/code/core/Mage/Core/Controller/Varien/Action.php(551): Mage::dispatchEvent('controller_acti...', Array)
#5 /Data/satvacart.com/public_html/app/code/core/Mage/Core/Controller/Front/Action.php(75): Mage_Core_Controller_Varien_Action->postDispatch()
#6 /Data/satvacart.com/public_html/app/code/core/Mage/Core/Controller/Varien/Action.php(422): Mage_Core_Controller_Front_Action->postDispatch()
#7 /Data/satvacart.com/public_html/app/code/core/Mage/Core/Controller/Varien/Router/Standard.php(254): Mage_Core_Controller_Varien_Action->dispatch('noRoute')
#8 /Data/satvacart.com/public_html/app/code/core/Mage/Core/Controller/Varien/Front.php(172): Mage_Core_Controller_Varien_Router_Standard->match(Object(Mage_Core_Controller_Request_Http))
#9 /Data/satvacart.com/public_html/app/code/core/Mage/Core/Model/App.php(354): Mage_Core_Controller_Varien_Front->dispatch()
#10 /Data/satvacart.com/public_html/app/Mage.php(684): Mage_Core_Model_App->run(Array)
#11 /Data/satvacart.com/public_html/index.php(89): Mage::run('base', 'website')
#12 {main}