I had the same issue with my WP site.
Refer to this page on editin wp-config.php file.
http://codex.wordpress.org/Editing_wp-config.php#FTP.2FSSH_Constants
if you dont have time to read through the whole page
here is what you need to do:
you might need to add the following lines at the end of the file:
define(‘FS_METHOD’, ‘value’); // either use direct, ssh2, ftpext or ftpsockets. in my case direct worked
define(‘FTP_BASE’, ‘/path/to/wordpress/’);
define(‘FTP_CONTENT_DIR’, ‘/path/to/wordpress/wp-content/’);
define(‘FTP_PLUGIN_DIR ‘, ‘/path/to/wordpress/wp-content/plugins/’);
define(‘FTP_PUBKEY’, ‘/home/username/.ssh/id_rsa.pub’); // if you are using SSL. else you may not add this line
define(‘FTP_PRIKEY’, ‘/home/username/.ssh/id_rsa’);// if you are using SSL. else you may not add this line
define(‘FTP_USER’, ‘username’);
define(‘FTP_PASS’, ‘password’);
define(‘FTP_HOST’, ‘ftp.example.org’);
define(‘FTP_SSL’, false);
?>
Check if this helps. .
CHeers 🙂