database error; install was fine

Hi,
My install was working fine until yesterday and then I started getting database error codes on the pages instead of my posts.
I had a php/mysql programmer do a table repair but it did not help. He feels that the database may not be the problem.
You can see the error codes for yourself at https://www.wirelessphoneinfo.com/.
Some of the error code given on the page is :
Database error: [Got error 28 from table handler]
SELECT DISTINCT link_category, cat_name, show_images, show_description, show_rating, show_updated, sort_order, sort_desc, list_limit FROM wp_links LEFT JOIN wp_linkcategories ON (link_category = cat_id) WHERE link_visible = ‘Y’ AND list_limit <> 0 ORDER BY cat_name
Any help would be greatly appreciated.