#1452 - Cannot add or update a child row: a foreign key constraint fails

Question

When i import a sql database to my godaddy server, it gave an error:

Error

SQL query:

--
-- Constraints for table `qa_uservotes`
--
ALTER TABLE `qa_uservotes`
  ADD CONSTRAINT `qa_uservotes_ibfk_1` FOREIGN KEY (`postid`) REFERENCES `qa_posts` (`postid`) ON DELETE CASCADE,
  ADD CONSTRAINT `qa_uservotes_ibfk_2` FOREIGN KEY (`userid`) REFERENCES `qa_users` (`userid`) ON DELETE CASCADE;

MySQL said: 

#1452 - Cannot add or update a child row: a foreign key constraint fails (`cnappnee`.`#sql-136f_14443702`, CONSTRAINT `qa_uservotes_ibfk_1` FOREIGN KEY (`postid`) REFERENCES `qa_posts` (`postid`) ON DELETE CASCADE)