I get a message that says, "Unable to grant access to this object. You may not be allowed to view it, or it may not exist."
This is usually a template set permissions problem. It can occur in object view or results view, whether searching or browsing.
To solve it, log into the Control Panel and make sure the current template set (specified in Collections -> Template Set Mapping) has access to all of the collections being searched. Go to Template Sets -> View All and click "Edit" next to the relevant template set. In the "Allowed Collections" section, make sure that if "All" is not checked, all of the collections being searched are.