DB QUERY ERROR (one_row_query()): Out of resources when opening file './musclecars_2017/admin_modules_seo.MYD' (Errcode: 24 - Too many open files)

SELECT IF(CHAR_LENGTH(seo_title), seo_title, (SELECT name FROM admin_modules WHERE moduleid = 2)) AS seo_title, seo_keywords, seo_description FROM admin_modules_seo WHERE groupid = 2 AND moduleid = 2