order number 00040004
Hi,
I try several times to install new extension and I still have this error message " The sef_ext install adapter does not exist." 
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Call stack
#	Function	Location
1	JApplicationCms->execute()	/var/www/vhosts/ip----server.net/mysite/administrator/index.php:47
2	JApplicationAdministrator->doExecute()	/var/www/vhostsip----server.net/mysite/libraries/cms/application/cms.php:252
3	JApplicationAdministrator->dispatch()	/var/www/ip----server.net/mysite/libraries/cms/application/administrator.php:152
4	JComponentHelper::renderComponent()	/var/www/ip----server.net/mysite/libraries/cms/application/administrator.php:98
5	JComponentHelper::executeComponent()	/var/www/vhosts/ip----server.net/mysite/libraries/cms/component/helper.php:372
6	require_once()	/var/www/vhosts/ip----server.net/mysite/libraries/cms/component/helper.php:392
7	JControllerLegacy->execute()	/var/www/vhosts/ip----server.net/mysite/administrator/components/com_installer/installer.php:19
8	InstallerControllerInstall->install()	/var/www/vhosts/ip----server.net/mysite/libraries/legacy/controller/legacy.php:728
9	InstallerModelInstall->install()	/var/www/vhosts/ip----server.net/mysite/administrator/components/com_installer/controllers/install.php:33
10	JInstaller->install()	/var/www/vhosts/ip----server.net/mysite/administrator/components/com_installer/models/install.php:158
11	JInstaller->setupInstall()	/var/www/vhosts/ip----server.net/mysite/libraries/cms/installer/installer.php:437
12	JInstaller->getAdapter()	/var/www/vhosts/ip----server.net/mysite/libraries/cms/installer/installer.php:817
13	JInstaller->loadAdapter()	/var/www/vhosts/ip----server.net/mysite/libraries/cms/installer/installer.php:2221
I follow the solution given on that page (
www.artio.net/support-forums/joomsef/com...nsions-in-joomla-3-3) but it doesn't work
When I want to use the installer on component, it returns here : index.php?option=com_installer
Any help will be appreciate :)