Fatal Error trying to activate plugin

Heyas! I’m just trying to install your plugin, but it keeps generating a fatal error whenever I try to activate it. Is this an issue with the plugin, or something on my end?

“Plugin could not be activated because it triggered a fatal error.

Fatal error: Call to a member function query() on a non-object in /home/vldrey5/public_html/wp-content/plugins/participants-database/classes/PDb_Init.class.php on line 158

Warning: Cannot modify header information – headers already sent by (output started at /home/vldrey5/public_html/wp-content/plugins/participants-database/classes/PDb_Init.class.php:158) in /home/vldrey5/public_html/wp-content/plugins/participants-database/classes/WP_Session.class.php on line 123″

https://ww.wp.xz.cn/plugins/participants-database/