To resolve this behavior, delete the Deleted Items.dbx file. Note that any items that remain in the Deleted Items folder are permanently deleted after you perform the deletion. Follow these steps:
Quit Outlook Express.
Right-click the Start button, and then click Find or Search.
Search for the Deleted Items.dbx file.
Right-click the file, click Delete, and then click Yes.
Start Outlook Express, and then try again to delete a message.