Failed to execute the SQL query

select  c.id, c.title, c.url, c.siteurl, f.name, c.parent, c.icon, c.descr, c.mode, c.lastmodified  from  wi_channels  c,  wi_folders  f  where f.id = c.parent and not(c.mode & 4)  and not(c.mode & 8)  and c.issponsor <> 2  order by f.position asc, c.linkedtous desc, STR_TO_DATE(c.lastmodified,'%a, %d %b %Y %T') desc

Error 2013: Lost connection to MySQL server during query