A PHP Error was encountered

Severity: Notice

Message: Trying to get property of non-object

Filename: models/settings.php

Line Number: 13

A PHP Error was encountered

Severity: Warning

Message: Attempt to assign property of non-object

Filename: models/settings.php

Line Number: 14

A PHP Error was encountered

Severity: Notice

Message: Trying to get property of non-object

Filename: controllers/index.php

Line Number: 30

Pagetag is not given, the default page by the settings doesn't exist and there's no page with home pagetag. What else could I have done?