Warning: file() [function.file]: URL file-access is disabled in the server configuration

If you are getting the above error then do the following changes into php.ini file or  .htaccess file :

nano php.ini
allow_url_fopen = On
allow_url_include = On

OR

nano .htaccess
<IfModule mod_php5.c>
php_admin_value allow_url_fopen On
php_admin_value allow_url_include On
</IfModule>

Done.