在PHP中使用副本时，文件夹上的权限被拒绝

So, I'm using a copy function to copy a folder and all of its contents. The problem is, I'm getting the following error when calling the function:

Warning: copy(//index.php): failed to open stream: Permission denied in /var/www/localhost/public_html/cms/app/functions.php on line 21

Warning: copy(//page.php): failed to open stream: Permission denied in /var/www/localhost/public_html/cms/app/functions.php on line 21

/* More of the same warnings below */

The copy function:

function recurse_copy($src,$dst) { 
$dir = opendir($src); 
@mkdir($dst); 
    while(false !== ( $file = readdir($dir)) ) { 
        if (( $file != '.' ) && ( $file != '..' )) { 
            if ( is_dir($src . '/' . $file) ) { 
                recurse_copy($src . '/' . $file,$dst . '/' . $file); 
            } 
            else { 
                copy($src . '/' . $file,$dst . '/' . $file); 
            } 
        } 
    } 
    closedir($dir); 
} 

Calling the function:

switch ($id) {
    case 1:
        copyfolder("install/default","/");
        break;
    default:
        header('Location: /cms/admin/templates');
        break;
}

The folder (install/default) which I'm trying to copy has rwxrwxrwx (077) permissions.

I've also tried adding Apache to the users group who has access to the /var/www/ folders, but with no luck.