A Update Error in PLSQLEO, PLEASE HELP ME!!!!

Question

There are two table based on two VOs.
The relation of two VOs is master-detail.
For some reason, there is no view-link between two VOs.
when I select different record(singleSelection) in master table, the detail table will show different data to user.
first,I select one record in master table ,and click a button, my program will use a value in profile to change the data in detail vo and commit it into database(by a plsql procedure in plsql eo's updateRow method).
second, I select another master record and click button again, error is occupied.
the error message is :
"Unable to perform transaction on the record.
Cause: The record contains stale data. The record has been modified by another user.
Action: Cancel the transaction and re-query the record to get the new data."
I am sure that befor the second action both master and detail VO are re-queryed,
and the api in plsql eo return a "S" to me.In fact, I call jtf_task_assignments_pub.update_task_assignment in this EO.
Who can tell me why this error was happened?
How can I resolve this problem??
Thanks a lot!

Answer 1

Please try redirecting to the same page after the first operation, prior to selecting the master again.
In processRequest, code must be there to re-init both the VOs.
Thanks
Tapash