I'm not the Administrator, but this is how sending a private message should work.
click 'users profile' from the side of a users post, or
from 'site info' at the top of the page you can go to ' who's registered' or ' who's on line' and click of the persons name to bring up a particular profile.
at the bottom of each profile is a lick' send user private message' click this and write yer message.
when finished click 'send' or 'submit'.
the message then goes into you 'out box' and 'stays' there till the recipient logs on and accepts the message. It doesn't appear in the 'sent' box until it is picked up by the user.
That's how it should work. Don't know if that helps.