Sessions problem brought down my whole site

I had two instances open of my shop and two instances open of the back end (2.0.11) and then just went out for 5 hours and then came back, pressed reload on the instances open in IE and got session db errors and then reloaded the instance open in the fireforx browser and got the same errors:

Database error: Can’t open file: ‘./cart/cscart_block_descriptions.frm’ (errno: 24) (1016)

Invalid query: SELECT cscart_blocks.*,cscart_block_descriptions.block,cscart_block_descriptions.block_id,cscart_block_links.item_ids,cscart_block_links.enable AS assigned FROM cscart_blocks LEFT JOIN cscart_block_links ON cscart_block_links.block_id = cscart_blocks.block_id AND (cscart_block_links.object_id = 0 OR cscart_block_links.object_id = ‘0’) LEFT JOIN cscart_block_descriptions ON cscart_block_descriptions.block_id = cscart_blocks.block_id AND lang_code = ‘EN’ WHERE 1 AND cscart_blocks.status = ‘A’ AND cscart_block_links.enable = ‘Y’ AND NOT FIND_IN_SET(‘index’, cscart_blocks.disabled_locations) AND (cscart_block_links.location = ‘all_pages’ OR cscart_block_links.location = ‘index’)

No idea what has happened, by my cart is so so 10 seconds on reload, 20 seconds to add a product…

This might have something to do with an spbot hitting my server and causing too may sql sessions to open up - I am not sure though.