Can anyone explain me this?

I use Jrun4 app server. I am creating a row in the database using entity beans. The child table record is created using DAO. Both the operations are happening in the same transaction. When i start the server n do the above operation i get parent key not exists exception while inserting the child. But when i repeat the same operation there is no such exception. Also when i restart the server n do the same operation i again get the same exception. what would be the problem?

[483 byte] By [Apprameyana] at [2007-11-26 17:14:14]