HELP! Mysql error

[♥akmac]

When ever I navigate more than three levels down in my categories, I'm getting this error:

 

1064 - 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 ') and c.categories_id = cd.categories_id and cd.language_id='1'

 

select c.categories_id, cd.categories_name, c.parent_id from categories c, categories_description cd where c.parent_id = '0' and c.categories_id in () and c.categories_id = cd.categories_id and cd.language_id='1' order by sort_order, cd.categories_name

 

[TEP STOP]

 

 

I haven't changed the db-what could be happening? this is in my live shop! Help....