problem loading sql into new database

[opto]

when loading old sql (MySQL 5.?) into a new one (Bitnami stack 5.5), I get the following sql error:

any idea what this means?

any help is appreciated,

Klaus

SQL query:


--
-- Constraints for table `chartdetails`
--
ALTER TABLE `chartdetails`
ADD CONSTRAINT `chartdetails_ibfk_1` FOREIGN KEY (`accountcode`) REFERENCES `chartmaster` (`accountcode`),
ADD CONSTRAINT `chartdetails_ibfk_2` FOREIGN KEY (`period`) REFERENCES `periods` (`periodno`);



MySQL said: Documentation
#1452 - Cannot add or update a child row: a foreign key constraint fails (`we_150809`.`#sql-acc_36`, CONSTRAINT `chartdetails_ibfk_2` FOREIGN KEY (`period`) REFERENCES `periods` (`periodno`))