Failed to execute the SQL query

select f.id, f.name, count(*) as cnt  from  item  i,  channels  c,  folders  f  where i.unread & 1 and not(i.unread & 8) and not(unread & 4)  and not(c.mode & 8)  and i.cid=c.id and c.parent=f.id  group by f.id

Error 1146: Table 'dh4772.item' doesn't exist