Help I tried to upgrade my site to 5.4.2.2 but when I click the upgrade link I get this error:

Fatal error: Call to a member function canWrite() on a non-object in /libraries/view.php on line 775

Initially I tried to download the update but it would not let me so i did it manually by replacing the concrete folder. when I clicked the update link I got that error. Now I can get to and move around my dashboard but my site is not updated and the site is freagged and gives me this error:

A database error occurred while processing this request.

Please help