Are you really proposing our disagreements with Europe, and the resultant rancor, stem from a failure to observe mutually agreed upon diplomatic protocols?
Yes and no. It is the perception of the United States that has suffered as a result of what, especially but not only, Rumsfeld has said.
As far as the disagreements are concerned, they are based on different ways of perceiving a certain situations. However, had the adminstration not made it politically impossible for Democratically elected officials in Europe to do anything but listen to their outraged constituency, those disagreements could have been smoothed over behind closed doors.
If you think that the current adminstration has handled Europe properly, then I would hate to see what a failure would look like.