Error when sending messages

Hello,

Another error encountered after a recent upgrade.  When I try to send a message to someone, the response is this:

Warning: main(BX_DIRECTORY_PATH_PLUGINSsafehtml/HTMLSax3.php): failed to open stream: No such file or directory in /var/www/vhosts/xxxxxxx.xxxx/httpdocs/plugins/safehtml/safehtml.php on line 22

Fatal error: main(): Failed opening required 'BX_DIRECTORY_PATH_PLUGINSsafehtml/HTMLSax3.php' (include_path='.:/usr/share/pear') in /var/www/vhosts/xxxxxxx.xxx/httpdocs/plugins/safehtml/safehtml.php on line 22

Can anyone offer any suggestions?

Thanks

Fixed it by adding this missing line to header.inc.php:

define('BX_DIRECTORY_PATH_PLUGINS', $dir['plugins']);