Oh darn! Well, I'm at a loss. Usually deleting one or all the the dbx files (except the Folders.dbx) takes care of corrupted files like that. The Folders.dbx file can also be deleted and rebuilt, but I've read that doing that will wipe out your settings, subscriptions to news feeds, personal folders, etc....if you have any of that. You'd have to do all that over again. The Folders.dbx is the "structure" of all the others, Inbox, Outbox, etc, etc.
I also found instructions for reinstalling OE without having to reinstall Internet Explorer all over again too...since OE is a part of IE. But I've never used it and I have no idea if doing that would also wipe out any personal folders and saved emails you've created, news feed settings, etc in your OE Identity. Supposedly you could back up all your messages and import them back in, but if it's a corrupted message and/or attachment that's causing all the trouble, then you wouldn't want to put the corrupted files back in. That could start the problem all over again. I'll post the instructions for reinstalling OE at the end of this if you want to go that route, but what about this idea first....
Could you not try to start again with a fresh Identity? Same ISP account, email address, etc. Just give it a different name for now, like YourNameTwo. That way you can keep the old one for awhile in case you need to go back and read the old emails for reference, if you need to keep them awhile.
I just did this myself as a test. First, I exported my address book as a comma separated file and saved it in my documents. Then I created a new identity called Test, but used all the other information that belonged to my primary email account with my ISP. I sent and received just fine. It re-downloaded the messages I'd left on my server as if they were brand new. Then I imported my address book back into the Test Identity by browsing to the csv file in my docs. It all seems to work okay.
If this works for you, then after you no longer need the corrupt identity, you can delete it and rename your good one back the way you had it.
If it doesn't work, then I would guess that Outlook Express itself is corrupted and you might want to consider reinstalling it using these directions.
QUOTE
Reinstall Outlook Express 6
NOTE: You must be logged on as Administrator or as a member of the Administrators group in order to perform this procedure.
Click Start , click Run , and then type the following command:
%systemroot%\inf
NOTE : There are no spaces at all in the preceding command line.
Click OK to open the INF folder.
Locate the file MSOE50.inf .
Right-click the file, and then click Install . This will reinstall the files that Outlook Express needs to proceed normally.
It will ask you to put your windows XP cd in the drive
Again, I don't know what that will do to your existing Identity or Identities and their folders, messages, address book,etc. It may or may not wipe them out. I just don't know. But if you've exported your address book like I talked about above, you'll be able to get that back easily.