MySQL Error

Original query: select pl.LesCode , PLesName , GrpCode , EDNT ,LesDesc, concat_ws( ' ',PProFname , PProLName) as ProName from PresentedLessons pl inner join SelectedCourses sc using(LesID) inner join lessons on (lessons.LesCode=pl.LesCode) inner join professors pr on ( pr.ProCode = pl.ProCode ) where pl.EduYear =1387 and pl.semester =2 and pl.LesStatus !=42 and CourseStatus !=?? and StNo ='????????' order by EDNT & 14

Error description: Got error 127 from storage engine