WordPress database error

Help me please… I don’t know what happened but all of a sudden all of my post are not showing and there’s an error message:

WordPress database error: [Can’t create/write to file ‘/tmp/#sql_1960_0.MYI’ (Errcode: 13)]
SELECT * FROM wp_posts WHERE 1=1 AND (post_status = “publish” OR post_author = 1 AND post_status != ‘draft’ AND post_status != ‘static’) GROUP BY wp_posts.ID ORDER BY post_date DESC LIMIT 0, 15

What is wrong? Please help