Event Calendar / Scheduler [Wordpress Plugin]

I installed the plugin and received errors when clicking the Plugins>Scheduler

here are the error message:

[code]Warning: include(DIR/groups.php) [function.include]: failed to open stream: No such file or directory in /hermes/waloraweb043/b184/moo.codingeducationcom/wp-content/plugins/event-calendar-scheduler/admin.php on line 2

Warning: include() [function.include]: Failed opening ‘DIR/groups.php’ for inclusion (include_path=’.:/usr/local/lib/php-5.2.17/lib/php’) in /hermes/waloraweb043/b184/moo.codingeducationcom/wp-content/plugins/event-calendar-scheduler/admin.php on line 2

Warning: Invalid argument supplied for foreach() in /hermes/waloraweb043/b184/moo.codingeducationcom/wp-content/plugins/event-calendar-scheduler/admin.php on line 3

Warning: implode() [function.implode]: Invalid arguments passed in /hermes/waloraweb043/b184/moo.codingeducationcom/wp-content/plugins/event-calendar-scheduler/admin.php on line 5[/code]

I have Wordpress 3.3.1 and all the directory and files and folders are 755 some are 644
is this a php version issue?, please guide me on what to do
The plugin works but my client is still seeing the error and there seem to be a problem with the Access Rights since default is the only thing that is visible.

please, open file wp-content/plugins/event-calendar-scheduler/admin.php and replace code: