Experiencing error after activating plugin

Hi,

I've uploaded the plugin and whenever I try to activate it, I get the following error:

Fatal error: Class 'BP_Group_Extension' not found in /home4/ivtech/public_html/streameventsnow.com/wp-content/plugins/bp-group-calendar/groupcalendar/bp-group-calendar.php on line 103

I've tried removing and installing it a few times (even deactivating all other BP plugins).

I'm also using the newest version.

Any help would be greatly appreciated.