After installing sef i get this error . i have read alot of topics before posting , no .ht exists , but i still get that error , what do i do wrong ?
Forbidden
You don't have permission to access /thumbnails.php on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.
Disable the SEF_URL and get rid of the .htaccess file that the plugin created within your coppermine root folder.