The PHP call is depreciated in the version of PHP you are running. Did you or your host recently update PHP? While VB 4.2.5 is compatible with PHP 7.1.x many of the plugins were not written for this version and will throw warning messages. This does not mean they will not work and you can just add:
Code:
php_flag display_errors off
to your .htaccess file to suppress the warning message(s). Eventually you might want to have hire a coder to bring the code up to date.