'sent' box is always at zero....just tried to send another PM to a member, checked sent box immediately, it says 0 sent......
are they sending and just not saving?

Could be in your settings.
click on 'user cp' then 'edit options' then scroll down to 'Messaging & Notification' - under 'Private Messaging' see if 'Enable Private Messaging' and 'Save a copy of sent messages in my Sent Items (http://www.chevelles.com/forums/private.php?folderid=-1) folder by default' are both checked.
Send me one and we'll see if it arrives.