Can’t Upgrade to 2.2.1 — Help!

I was running 2.1.3 and followed the steps upgrade and uploaded the 2.2.1 files and when I go to the upgrade.php page I get:

Warning: main(/home/sangrial/public_html/wp-includes/wp-db.php): failed to open stream: Permission denied in /home/sangrial/public_html/wp-settings.php on line 100

Fatal error: main(): Failed opening required ‘/home/sangrial/public_html/wp-includes/wp-db.php’ (include_path=’.:/usr/local/lib/php’) in /home/sangrial/public_html/wp-settings.php on line 100

I have no idea what to do at this point. Seems like every time I upgrade it is some new nightmare because I am not very tech-savvy.