"The Operation Failed" Error

There is a known incompatibility between Skype and Outlook 2003 that results in "The operation failed" error whenever you are trying to send, reply, or forward an email message while Skype is running.

The solution is to exit Skype whenever Outlook is open. Right-click on the Skype icon on the right side of the Taskbar and choose Exit from the resulting menu before starting Outlook. You can start Skype again when Outlook is closed.