Probs with upgrade (2.0.10 to 2.2.1)

I have just rcently upgraded from 2.0.10 to 2.2.1. Just like the guide says i;
1. backup my database
2. backup my files in local
3. diactivate plugins
4. upload the new package overwriting the old ones
5. i retain my .htaccess and wp-config file.

the result is chaos.
The probs happened after the upgrade;

1. read more for posts dont work. showed an error page or somethimes blank page
2. Wp-Stats showed this error;

WordPress database error: [You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ‘ COUNT(*) AS ‘total_links’ FROM wp_links INNER JOIN ON .cat_id = wp_links.lin’ at line 1]
SELECT .cat_name, COUNT(*) AS ‘total_links’ FROM wp_links INNER JOIN ON .cat_id = wp_links.link_category GROUP BY .cat_id ORDER BY total_links DESC

3. Cant viewing or edit anything in Manage>Posts
4. My drafts showed in frontend ‘Recent Post’. Upon clicking showed blank pages.
5. many more to be stated.

Can someone please advice which area that i should troubleshoot first?

Cheers