My website is hosted on godaddy and the version of WP I have is 3.1.1. I first tried to do the automatic upgrade, but kept getting a message saying that I had a permission issue. So I decided to download 3.4 and upgrade manually using the steps found here: Updating_WordPress. I went through step 1 and 1.5. I then went to my upgrade.php and it said I needed to upgrade my database. I then got the error: "Fatal error: Class 'WP_Theme' not found in <mywebsite>\httpdocs\wp-includes\theme.php on line 106". Is there something I did wrong, or a way to fix this?
Here's line 106 from theme.php:
return new WP_Theme( $stylesheet, $theme_root );
Apparently the class WP_Theme isn't defined in theme.php, so where is it defined?