"Fatal error: Call to a member function hasPluginAttachments() on a non-object in C:\UniServer\www\nttac\sites\all\modules\heartbeat\views\views_handler_field_heartbeat_attachments.inc on line 20 "

Trying to use a view displaying heartbeat activity as a site landing page. getting the above message.

Using version 7.x-1.1; have disabled the sub-module defaults, sub module plugin and the sub module comments.

problem goes away when defaults is re-enabled, but that enables significant amouts of unneeded templates, streams, etc.