[Plugin: Participants Database] Error messages

I received these error messages and am not sure why…

also is there a way to categorize participants? Photographers, Accountants, etc?

Warning: include(database.php) [function.include]: failed to open stream: No such file or directory in /home/hybrid/public_html/wp-content/plugins/participants-database/participants-database.php on line 422

Warning: include(database.php) [function.include]: failed to open stream: No such file or directory in /home/hybrid/public_html/wp-content/plugins/participants-database/participants-database.php on line 422

Warning: include() [function.include]: Failed opening ‘database.php’ for inclusion (include_path=’.:/usr/lib/php:/usr/local/lib/php’) in /home/hybrid/public_html/wp-content/plugins/participants-database/participants-database.php on line 422

https://www.ads-software.com/extend/plugins/participants-database/