Hello,
I installed following extension.
Kancart Mobile Web & Mobile APP – 108 Themes in 1 Freemium Mobile web & Mobile APP service
http://www.magentocommerce.com…..rvice.html

But after that, dashboard page came to not be shown.
I checked Error log as following.
a:5:{i:0;s:75:”Mage registry key “_singleton/Kancart_MobileApi_Helper_Data” already exists”;i:1;s:1329:”#0 /home7/hokkaid4/public_html/app/Mage.php(223): Mage::throwException(‘Mage registry k…’)
#1 /home7/hokkaid4/public_html/app/Mage.php(477): Mage::register(‘_singleton/Kanc…’, false)
#2 /home7/hokkaid4/public_html/includes/src/__default.php(21427): Mage::getSingleton(‘Kancart_MobileA…’)
#3 /home7/hokkaid4/public_html/app/Mage.php(448): Mage_Core_Model_App->dispatchEvent(‘controller_acti…’, Array)
#4 /home7/hokkaid4/public_html/includes/src/__default.php(14078): Mage::dispatchEvent(‘controller_acti…’, Array)
#5 /home7/hokkaid4/public_html/includes/src/Mage_Adminhtml_Controller_Action.php(160): Mage_Core_Controller_Varien_Action->preDispatch()
#6 /home7/hokkaid4/public_html/includes/src/__default.php(13958): Mage_Adminhtml_Controller_Action->preDispatch()
#7 /home7/hokkaid4/public_html/includes/src/__default.php(18331): Mage_Core_Controller_Varien_Action->dispatch(‘login’)
#8 /home7/hokkaid4/public_html/includes/src/__default.php(17865): Mage_Core_Controller_Varien_Router_Standard->match(Object(Mage_Core_Controller_Request_Http))
#9 /home7/hokkaid4/public_html/includes/src/__default.php(20465): Mage_Core_Controller_Varien_Front->dispatch()
#10 /home7/hokkaid4/public_html/app/Mage.php(684): Mage_Core_Model_App->run(Array)
#11 /home7/hokkaid4/public_html/index.php(87): Mage::run(”, ‘store’)
#12 {main}”;s:3:”url”;s:70:”/index.php/admin/dashboard/index/key/4c02dd393ec574045127b07d2b88e50c/”;s:11:”script_name”;s:10:”/index.php”;s:4:”skin”;s:5:”admin”;}

But I have no idea above problem.
Please help me about that.
I appreciate your help.
Thank you.