1 - Can't create/write to file '/tmp/#sql_506_0.MYI' (Errcode: 28)

select cd.categories_description, c.categories_id, cd.categories_name, cd.categories_heading_title, c.categories_image, c.parent_id from categories c, categories_description cd where c.categories_status = '1' and c.parent_id = '620' and c.categories_id = cd.categories_id and cd.language_id = '1' order by sort_order, cd.categories_name

[XT SQL Error]