When clicking SEND in OWA, messages go to the DRAFT folder and do not get sent out.

When users access OWA, the can create a message with no problem. When they send the message, the window closes and you think the message went out. A careful look and you notice that the message actually went to the DRAFT folder and did not go out. If you look at the message in the draft folder, the To: field shows the correct person the message was intended for, but all text that the user had typed is gone. If the message was a reply, the original email info is there but no comments that the user entered.

When I connect to the user's mailbox using my PC (IE7 & Firefox), I have no problem [Connecting remotely through the firewall as my users would]. Not all users are having the problem, and it seems like it's from their home PCs. For the users that are having the problem, the problem is NOT intermittent. All messages are not being sent but rather saved in the draft folder.

I am running Exchange 2003 w/ SP2, running on Windows 2003 SP1.
Clients reporting the problem are on Win2k and XP. Can't determine SP levels or IE level at this time.