error updating to 3.5

– To rule out any theme-specific issue, try switching to the unedited default theme for a moment using the WP dashboard. If you don’t have access to your admin area, you can switch to the default theme by renaming your current theme’s folder in wp-content/themes via FTP or SFTP or whatever file management application your host provides.

lines 3024 to 3043 in class-simplepie.php read

public function __call($method, $args)
	{
		if (strpos($method, 'subscribe_') === 0)
		{
			$level = defined('E_USER_DEPRECATED') ? E_USER_DEPRECATED : E_USER_WARNING;
			trigger_error('subscribe_*() has been deprecated, implement the callback yourself', $level);
			return '';
		}
		if ($method === 'enable_xml_dump')
		{
			$level = defined('E_USER_DEPRECATED') ? E_USER_DEPRECATED : E_USER_WARNING;
			trigger_error('enable_xml_dump() has been deprecated, use get_raw_data() instead', $level);
			return false;
		}

		$class = get_class($this);
		$trace = debug_backtrace();
		$file = $trace[0]['file'];
		$line = $trace[0]['line'];
		trigger_error("Call to undefined method $class::$method() in $file on line $line", E_USER_ERROR);
	}

lines 74 to 82 of class-twitter.php read

public function __construct($username, $limit = 1, $list_mode = false, $extract_info=false) {
		$this->username = $username;
		$this->limit = $limit;
		$this->list_mode = $list_mode;
		if (method_exists(parent,'__construct')) {
			parent::__construct();
		} else {
			$this->SimplePie();
		}

have you tried switching to the default theme as suggested in my previous post?

Yes. Now the page is blank, but at least there is no error message!

Any suggestions on what to do next?

Try:

-flushing any caching plugins you might be running, as well as server and/or browser caches.

-deactivating ALL plugins (yes, all) temporarily to narrow down the problem. If the problem goes away, re-activate them individually (one-by-one) to find the problematic plugin(s). If you can’t get into your admin dashboard, try resetting the plugins folder by FTP or phpMyAdmin. Sometimes, an apparently inactive plugin can still cause problems (because the hooks remain unless plugins completely removed or some plugins stick around in cached files. So by renaming the folder, you break them and force them inactive). If applicible, also remember to deactivate any plugins in the mu-plugins folder. The easiest way is to rename that folder to mu-plugins-old

-If that does not resolve the issue, try manually re-uploading all files and folders EXCEPT the wp-config.php file and the /wp-content/ directory from a fresh download of WordPress. This should replace your core files without changing your content and settings in wp-config.php file and the /wp-content/ directory. Read the Manual Update directions first!

I to am getting an error while updating to 3.5. Fatal error: Call to undefined function wp() in /home/royseas/public_html/setup/wp-blog-header.php on line 14

This is the second one. The first one was:
Fatal error: Call to undefined function wp() in /home/royseas/public_html/setup/wp-admin/admin.php on line 32

Any ideas? This is the first site that has done this. All other sites I host updated with no issues.

When I deactivated my plugins (through the scary phpMyAdmin method), I was able to login through the dashboard and change my theme and it all worked out. The site is much better now than it ever was. Thanks, WordPress!

You are welcome ??