Please go to Foursquare user applications page https://foursquare.com/developers/apps , create a new application, and in the line 23 set the client_id to Client ID and client_secret with Client Secret.  The callback URL must be http://erp.leaf.com.my/webmail/modules/OAuthIntegratorWebclient/Classes/OAuthClient/login_with_foursquare.php