eXtplorer - PHP-based File Manager

This is the message, that I get....do you have any idea as to how to solve the problem?

Warning: require_once() [function.require-once]: SAFE MODE Restriction in effect. The script whose uid is 48679 is not allowed to access /usr/share/php/PEAR.php owned by uid 0 in /public/sites/www.poteind.nl/joomla/administrator/components/com_extplorer/libraries/FTP.php on line 33

Warning: require_once(/usr/share/php/PEAR.php) [function.require-once]: failed to open stream: No such file or directory in /public/sites/www.poteind.nl/joomla/administrator/components/com_extplorer/libraries/FTP.php on line 33

Fatal error: require_once() [function.require]: Failed opening required 'PEAR.php' (include_path='.:/usr/share/php:/usr/share/pear') in /public/sites/www.poteind.nl/joomla/administrator/components/com_extplorer/libraries/FTP.php on line 33

Kind regards,
Marleen