Can't log into admin panel on Magento

[darkthorn]

Hello, 

Today while working on my store I lost the acess to my admin panel. I get the following error:

Fatal error: Call to a member function setActive() on a non-object in /home/wwwimper/public_html/includes/src/Mage_Adminhtml_Controller_Action.php on line 104

Checking the errors file on the var/reports directoy I get this:

a:5:{i:0;s:65:"Mage registry key "_singleton/catalogsearch2/feed" already exists";i:1;s:1475:"#0 /home/wwwimper/public_html/app/Mage.php(223): Mage::throwException('Mage registry k...')
#1 /home/wwwimper/public_html/app/Mage.php(477): Mage::register('_singleton/cata...', false)
#2 /home/wwwimper/public_html/includes/src/__default.php(22147): Mage::getSingleton('catalogsearch2/...')
#3 /home/wwwimper/public_html/app/Mage.php(448): Mage_Core_Model_App->dispatchEvent('controller_acti...', Array)
#4 /home/wwwimper/public_html/includes/src/__default.php(14381): Mage::dispatchEvent('controller_acti...', Array)
#5 /home/wwwimper/public_html/includes/src/Mage_Adminhtml_Controller_Action.php(160): Mage_Core_Controller_Varien_Action->preDispatch()
#6 /home/wwwimper/public_html/app/code/core/Mage/Adminhtml/controllers/System/ConfigController.php(51): Mage_Adminhtml_Controller_Action->preDispatch()
#7 /home/wwwimper/public_html/includes/src/__default.php(14261): Mage_Adminhtml_System_ConfigController->preDispatch()
#8 /home/wwwimper/public_html/includes/src/__default.php(18750): Mage_Core_Controller_Varien_Action->dispatch('edit')
#9 /home/wwwimper/public_html/includes/src/__default.php(18280): Mage_Core_Controller_Varien_Router_Standard->match(Object(Mage_Core_Controller_Request_Http))
#10 /home/wwwimper/public_html/includes/src/__default.php(21176): Mage_Core_Controller_Varien_Front->dispatch()
#11 /home/wwwimper/public_html/app/Mage.php(684): Mage_Core_Model_App->run(Array)
#12 /home/wwwimper/public_html/index.php(83): Mage::run('', 'store')
#13 {main}";s:3:"url";s:77:"/index.php/admin123/system_config/index/key/4b93c4f99c953afdea77fd97de23c63a/";s:11:"script_name";s:10:"/index.php";s:4:"skin";s:5:"admin";}

Any ideas? I am a newbie with magento :/

[hesper]

Try

php -f shell/compiler.php disable
php -f shell/compiler.php clear
php -f shell/compiler.php compile

[theonlytoshka]

Thank you very much your suggestion worked! I knew i should've disable the compiler before installing the extension but i ignored it and this was a quick fix. Thank you!!

[andrew_hague]

Do I put this in SSH?

[theonlytoshka]

Yes SSH to the root directory of your store, and type the commands in there.