www.BoundAnna.com

I've tried to send a couple of private messages, but they are not appearing in my "sent" folder. They are stuck in my "outbox".

please advise....

They will remain there until the recipient opens them. That way, you know when they are read, at which point, the message will automatically move to SENT folder.

Exactly as Shannon just said. Phpbb boards put messages in the outbox until the recipient has read them, after which they move to Sent. If they stay in the outbox that means the recipient hasn't read them yet.