Messaging bug in Pocket PC 5.0

Hello Friends,
I am sending emails(local and external) using MAPI but
sometimes my emails remains in \Windows\Messaging folder and does not appear
in Pocket PC Inbox (local emails) or outbox(external emails). I can see a
file corresponding to every email sent by my application in
\Windows\Messaging folder.

Any idea why ?

Thanks in advance

Regards,
-Santosh