Troubles after trying to upgrade to 2.1pl

Looks like your cache directory and it’s contents are not writable by the PHP process.

The folders inside the core/cache are all 775 Owner: apache
The php files inside the core/cache are all 664 Owner: apache

I erased the core/cache multiple times but it made no difference.

What is the best to do now, how can I make the cache folder and it contents writable by the PHP proces.

The folders inside the core/cache are all 775 Owner: apache
The php files inside the core/cache are all 664 Owner: apache

Try 777 and see if the problem goes away, if it does ask the hosts what the correct file permissions should be as it can differ from server to server.