Tags in post go to 404 page

when you click a tag in a post it goes to 404 not found, I’ve searched all over this site and cant find an answer. I use permalinks /%postname% .html. I have category in category and tag in tag fields. I have updated my .htaccess according to WP.

IndexIgnore .htaccess */.??* *~ *# */HEADER* */README* */_vti*

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /wordpress/
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /wordpress/index.php [L]
</IfModule>
I am using border.px theme with relatively few plugins. I do not have a tag cloud in my sidebar…

when a tag is clicked it shows the address in the address bar as http://www.mysite/tag/whatever and the 404 response.

It is probable something very simple but I just cannot find it, I have been looking for a week now.