Increaseing Memory usage

Hi All,
I'm writing a API to extracting mails from MS Outlook using MAPI.
To get top level folders in a store I do following steps
       1. Get MAPIFolder  interface from MsgStore Interface.
       2. Call GetHierarchyTable method of MAPIFolder interface.
for first container(Store) all going fine but for more than one container 
the after the same call the memory usage increases heavily.
        can any one help me.
Thanking you,





-- 
    Regards,
 Digambar Borse