Warning: require_once(PEAR.php): Failed to open stream: No such file or directory in /home/lab/brc/WWW/Ch27/Net_SMTP-1.4.2/Net/Socket.php on line 22

Fatal error: Uncaught Error: Failed opening required 'PEAR.php' (include_path='.:/usr/local/share/pear') in /home/lab/brc/WWW/Ch27/Net_SMTP-1.4.2/Net/Socket.php:22 Stack trace: #0 {main} thrown in /home/lab/brc/WWW/Ch27/Net_SMTP-1.4.2/Net/Socket.php on line 22