How do I fix the error?

Warning: require_once(/home/chadegan/domains/chadegan.com/public_html/concrete/helpers/concrete_avatar.php): failed to open stream: No such file or directory in /home/chadegan/domains/chadegan.com/public_html/concrete/core/libraries/loader.php on line 297 Fatal error: require_once(): Failed opening required '/home/chadegan/domains/chadegan.com/public_html/concrete/helpers/concrete_avatar.php' (include_path='/home/chadegan/domains/chadegan.com/public_html/libraries/3rdparty:/home/chadegan/domains/chadegan.com/public_html/concrete/libraries/3rdparty:.:/usr/local/php5/lib/php') in /home/chadegan/domains/chadegan.com/public_html/concrete/core/libraries/loader.php on line 297