I fixed this by replacing the following lines in twitter-tools.php :
define('AKTT_API_POST_STATUS', 'https://twitter.com/statuses/update.json');
define('AKTT_API_USER_TIMELINE', 'https://twitter.com/statuses/user_timeline.json');
define('AKTT_API_STATUS_SHOW', 'https://twitter.com/statuses/show/###ID###.json');
define('AKTT_PROFILE_URL', 'https://twitter.com/###USERNAME###');
define('AKTT_STATUS_URL', 'https://twitter.com/###USERNAME###/statuses/###STATUS###');
define('AKTT_HASHTAG_URL', 'https://search.twitter.com/search?q=###HASHTAG###');
by this :
define('AKTT_API_POST_STATUS', 'https://api.twitter.com/1.1/statuses/update.json');
define('AKTT_API_USER_TIMELINE', 'https://api.twitter.com/1.1/statuses/user_timeline.json');
define('AKTT_API_STATUS_SHOW', 'https://api.twitter.com/1.1/statuses/show.json?id=###ID###');
define('AKTT_PROFILE_URL', 'https://twitter.com/###USERNAME###');
define('AKTT_STATUS_URL', 'https://twitter.com/###USERNAME###/statuses/###STATUS###');
define('AKTT_HASHTAG_URL', 'https://search.twitter.com/search?q=###HASHTAG###');