Veja como corrigir isso
STOP SLAVE;
SET GLOBAL SQL_SLAVE_SKIP_COUNTER = 1;
use bgbilling
DROP TABLE IF EXISTS contract_status_balance_dump;
CREATE TABLE contract_status_balance_dump( UNIQUE(cid) )
SELECT cid, MAX(yy*12+(mm-1))%12 + 1 AS mm,FLOOR(MAX(yy*12+(mm-1)) / 12) AS yy
FROM contract_balance GROUP BY cid;
START SLAVE;
SHOW SLAVE STATUS\G