If you didn’t have any such problems before with the same host, your hosting company probably changed some system settings.
File: /var/www/vhosts/makethemclick.com.au/httpdocs/assets/snippets/ajaxSearch/classes/ajaxSearch.class.inc.php
^ this indicates that the AjaxSearch script (snippet) is calling the set_time_limit() PHP function, not MODx per se. Hence, for an intermediate solution either deactivate AjaxSearch altogether in your website, or comment out the corresponding line in the assets/snippets/ajaxSearch/classes/ajaxSearch.class.inc.php script:
just add // in front of line 78:
// set_time_limit($asCfg->cfg[’timeLimit’]);
Or, you could also try to suppress error messages with @:
@set_time_limit($asCfg->cfg[’timeLimit’]);