Error message

• Notice: Trying to access array offset on value of type null in calendar_plugin_row->render() (line 439 of sites/all/modules/calendar/includes/calendar_plugin_row.inc).
• Notice: Trying to access array offset on value of type null in calendar_plugin_row->render() (line 439 of sites/all/modules/calendar/includes/calendar_plugin_row.inc).
• Notice: Trying to access array offset on value of type null in calendar_plugin_row->render() (line 439 of sites/all/modules/calendar/includes/calendar_plugin_row.inc).
• Notice: Trying to access array offset on value of type null in calendar_plugin_row->render() (line 439 of sites/all/modules/calendar/includes/calendar_plugin_row.inc).
• Notice: Trying to access array offset on value of type null in calendar_plugin_row->render() (line 439 of sites/all/modules/calendar/includes/calendar_plugin_row.inc).
• Notice: Trying to access array offset on value of type null in calendar_plugin_row->render() (line 439 of sites/all/modules/calendar/includes/calendar_plugin_row.inc).
• Notice: Undefined index: groupby_times in template_preprocess_calendar_week() (line 485 of sites/all/modules/calendar/theme/theme.inc).
• Notice: Undefined index: groupby_times in template_preprocess_calendar_week() (line 489 of sites/all/modules/calendar/theme/theme.inc).
• Notice: Undefined index: groupby_times in template_preprocess_calendar_week() (line 485 of sites/all/modules/calendar/theme/theme.inc).
• Notice: Undefined index: groupby_times in template_preprocess_calendar_week() (line 489 of sites/all/modules/calendar/theme/theme.inc).