plugin causing website to not load or HTTP 500 error

Here is the log from our web host.

[Tue Aug 09 15:57:39.230347 2016] [:error] [pid 29379] [client 66.249.83.209:35612] FastCGI: server "/dev/shm/macedge-php.fcgi" stderr: PHP message: PHP Fatal error: Call to a member function is_main_query() on a non-object in /home/macedge/www/wp-content/plugins/events-and-bookings/lib/default_filters.php on line 122
[Tue Aug 09 15:59:01.857041 2016] [:error] [pid 25143] [client 74.92.60.149:31031] FastCGI: server "/dev/shm/macedge-php.fcgi" stderr: PHP message: PHP Fatal error: Call to a member function is_main_query() on a non-object in /home/macedge/www/wp-content/plugins/events-and-bookings/lib/default_filters.php on line 122
[Tue Aug 09 15:59:19.337695 2016] [:error] [pid 31152] [client 74.92.60.149:24378] FastCGI: server "/dev/shm/macedge-php.fcgi" stderr: PHP message: PHP Fatal error: Call to a member function is_main_query() on a non-object in /home/macedge/www/wp-content/plugins/events-and-bookings/lib/default_filters.php on line 122, referer: http://www.macedge.com/servicedropoff/
[Tue Aug 09 16:00:10.816334 2016] [:error] [pid 32200] [client 24.233.114.115:54086] FastCGI: server "/dev/shm/macedge-php.fcgi" stderr: PHP message: PHP Fatal error: Call to a member function is_main_query() on a non-object in /home/macedge/www/wp-content/plugins/events-and-bookings/lib/default_filters.php on line 122
[Tue Aug 09 16:00:22.865539 2016] [:error] [pid 32167] [client 24.233.114.115:54090] FastCGI: server "/dev/shm/macedge-php.fcgi" stderr: PHP message: PHP Fatal error: Call to a member function is_main_query() on a non-object in /home/macedge/www/wp-content/plugins/events-and-bookings/lib/default_filters.php on line 122
[Tue Aug 09 16:00:39.521634 2016] [:error] [pid 31315] [client 70.88.242.165:60067] FastCGI: server "/dev/shm/macedge-php.fcgi" stderr: PHP message: PHP Fatal error: Call to a member function is_main_query() on a non-object in /home/macedge/www/wp-content/plugins/events-and-bookings/lib/default_filters.php on line 122
[Tue Aug 09 16:00:44.507145 2016] [:error] [pid 29423] [client 70.88.242.165:60069] FastCGI: server "/dev/shm/macedge-php.fcgi" stderr: PHP message: PHP Fatal error: Call to a member function is_main_query() on a non-object in /home/macedge/www/wp-content/plugins/events-and-bookings/lib/default_filters.php on line 122
[Tue Aug 09 16:00:46.595965 2016] [:error] [pid 29422] [client 70.88.242.165:60070] FastCGI: server "/dev/shm/macedge-php.fcgi" stderr: PHP message: PHP Fatal error: Call to a member function is_main_query() on a non-object in /home/macedge/www/wp-content/plugins/events-and-bookings/lib/default_filters.php on line 122
[Tue Aug 09 16:00:52.941958 2016] [:error] [pid 4745] [client 70.88.242.165:60097] FastCGI: server "/dev/shm/macedge-php.fcgi" stderr: PHP message: PHP Fatal error: Call to a member function is_main_query() on a non-object in /home/macedge/www/wp-content/plugins/events-and-bookings/lib/default_filters.php on line 122

I disable Yoast SEO and the issue seems to go away... but we need Yoast.