Access forbidden in linux mint for apache localhost

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http://stackoverflow.com – I am doing PHP development using Linux OS ,Lampp Apache server.I changed the default root folder htdocs to another folder PHP on my desktop. When I create a hello.php file in the folder ,I can see it in browser and works well. But I have another folder inside this root folder called 'front_end'.When I try to see it in browser using http://localhost/front_end ,i get access forbidden. Firebug shows 'Access forbidden' How can I get access to this folder using localhost? Another user asked a similar question on stackoverflow ,but it didn't help. Ubuntu/Apache2/ Forbidden/Permission error (HowTos)