How can I fix Fatal error 103 on BC Group Calendar

Used your Dev Dashboard to install BP Grpup Calendar. After the installation i get this error: "Fatal error: Class 'BP_Group_Extension' not found in /home/tolkexiq/public_html/wp-content/plugins/bp-group-calendar/groupcalendar/bp-group-calendar.php on line 103", and the site is down.

How can I fix this? As far I see it, you are the one to blame.