Categories permalinks problem :(

Hi!

I am a newbie to WordPress, searched through forum, but never found the solution to my problem:

1. After editing Permalink Structure in Admin Panel / Options (in Structure: field I’ve typed “/%year%/%monthnum%/%day%/%postname%/” and in Category base: I’ve typed “/content”) WordPress gave me some strange errors on a main page:

“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 ” at line 1]
SELECT category_nicename FROM wp_categories WHERE cat_ID=”

2. As a man with no knowledge of php, I got scared 🙂 and erased everything from Permalink Structure fields and updated (returned to defaults :P). Errors disappeared, but now on a main page all categories links at the bottom of each post look like “http://www.jamert.ee/v3/?cat=” with no category ID at the end!

How do I fix it?? Please help!

My blog: http://www.jamert.ee
Example post: http://www.jamert.ee/v3/?p=96 (categories after the last image)
My server information (I do not understand it myself :P): http://www.jamert.ee/work/phpinfo.php

Thanks in advance!