Messages appear on both forums?

[chess1]

i am creating sub forums.
My problem is after i create sub forum if i post any message on sub forums it appears on parent forum too?
i don't want this happen.
Thank you for your help
Sorry i couldn't find solution myself.

Edit;
i have posted same issue in v bulletin.com forum and got response i have to modify the code.
this is the pics in here.
can anyone help me how to do so.
i want to have forums have only message which posted on them. not the parent and child forum.
doubling the messages.
thank you