Fatal Error

When I point my browser to the update.php file I get a 500 error:

500 Error – Internal Server Error
This error was caused due to an unexpected difficulty in fulfilling the user request. The most likely cause of this error is a crashed or error’d CGI script or program. Please verify that the program is properly compiled and/or operational and carry out any necessary debugging.
If you are not responsible for this resource, please send a bug-report to the address listed below describing your problem. Please include in the report the date, time, your e-mail address, the website on which this error occured and what you were attempting to do when this error occured. Your compliance is appreciated.

Then I try to login to the wp-admin page and get the Index page. When I click on Parent Directory I get:

Fatal error: Call to undefined function: require_wp_db() in /hsphere/local/home/ttaylor1/worldclasspoetryblog.com/wordpress/wp-settings.php on line 206

I wonder if this is as a result of not disabling my plugins before I started? I didn’t read the extended upgrade instructions until after I received these errors. Didn’t know they existed. I tried following the 5 minute upgrade instructions and now I’m in trouble. Any help would be appreciated.