A common cause for this error, is having too many items in the deleted folder. Or a folder/box that has reached it's size limit. When the deleted folder hits its limit, you need to empty it. (Sorry but I don't know the crunched size/limitation numbers off the top of my head.)
Let's try something easy first. One way to delete these items, without addressing the cause, is to hold the shift key when you delete
to bypass the Deleted items folder. Or another possible work-around is to open the send to folder and select and delete a few or fewer items at the same time. Repeat this procedure until all the items that you want to delete have been deleted.
If you can't delete them, can you move them, to another folder (that you make) and then delete that folder? Just to clarify...are these messages in the "Outbox" or copies in the "Sent" box. Does outlook have a box, literally, named "send"?
I don't know how much help, ^the above, will be for you. I have office 2000 and don't use Outlook but prefer OE. Therefore specifc Outlook 2003 fixes are pretty much beyond me. I did think that the above method may just work for ya' though and thought it worth a try so I took a shot. (Not knowing if you have searched this boards "Archived posts", may I suggest that? It's filled with tons of OE info. Perhaps Outlook will produce similar bountiful hits. Barring that I will be glad to look for possible alternative solutions, with the steps needed for Outlook 2003, if another member doesn't supply the method/fix you'll need in the meantime.
--Back from google shopping and here's what I came up with---
If this is the outbox, perhaps this will apply but please... please take all
precautions needed to make sure your current mail data is backed up so you can restore all
should it become neccessary. While we are only messing with a few spoiled apples, trying to get rid them may damage the whole barrel. (< Forgive the bad metaphor). That said: http://www.outlook-tips.net/howto/stuck_message.htm
Or as a twist to the ^above keep the new pst:
Create a new PST, make it your default delivery location, and move
everything from your old PST (except the items you don't want
) to it. Close and delete the old PST.
-Now for a possible fix that may cause this------------------
Have you patched your office program? You may need to update.
Shoot....! I had the link but I closed the window. Be back in a bit.....
As a side note, I did see a couple of references hinting at a possible snafu if this was an upgraded install of office 2003 (from office xp for example) and the older files where from the previous version. So far the advice noted has been to create a new profile but there has to a better solution than that, don't you think? I won't bother with this "monkey wrench" as I don't know if it applies, I just thought it was an interesting "hmmmmmm".