New Post: Outlook 2010, "Read Receipt" msg stuck in outbox

Hi,
Have a message (pure text message, w/o any attachment) stuck in outlook (using outlook 2010, 32bit, Windows 7).
When trying to send out messages, all messages will send out except the one problematic message.
Then, will attempt to send the problematic one but will close itself and restart the program.
Tried already several delete methods;

1. Off line method >> it didn't delete
2. Bill's Method >> found the relevant message but it didn't delete
3. Then tried the MFCMAPI (my message is a "Read Receipts" message)
   Found easily the message under the "Root Container", applied 'abort submit', then 'delete item', etc.
   (followed instructions: http://www.howto-outlook.com/howto/deletereadreceipt.htm )
   Tried to delete, but it didn't delete...
   

Note: An action that was done shortly before composing this problematic email was obtaining a digital ID.
I'm not sure if the 'stuck problem' is related at all to this action.

I would appreciate any help trying to delete the stubborn (False) message.
Thank you in advance.
GD