This is something that I ran across using a version control system that perplexed me. It couldn’t hit me more as a poor case of alerting in an application.
ClearCase is a version control package owned now by IBM. I am unsure if we are using the latest version of this package, or if the company is too cheap to spring for an update. If it has been updated I only hope that things have gotten much easier to use.

This alert appears after attempting to check in files with out placing a WO in the comment field. The usability nightmare begins…
What is a WO, or a CI? Vague abbreviations in an alert are never a good idea. This is lessened due to the audience using this package, as they will generally know what is meant, but I still had to read this error a few times to get it right. WO = Work Order, a trouble report that is a commonly known abbreviation — but I see little reason not to just spell it out. CI = Check In… I think. I really am not sure. They spell out “check in” later, so why can’t we be clear!?
What really caught my eye though are the options available to us on this dialog. Yes, No and Abort.
First, what’s the question I’m answering to? The dialog does not ask anything, or infer anything, that would necessitate a Yes or No reply.
Abort!? That sounds really serious! I mean… damn! We’re going to abort… something… I think. The dialog tells me the application has already refused to check the file in, so what exactly am I aborting?
Ultimately, all three buttons do exactly the same thing. They all close the dialog and force you to begin the process over again. Something a single “Ok” or “Close” button would have done, with less confusion.
UPDATE:
Another time this error appears is when you type the required information is not inputed correctly. It must be typed in a very specific way, else the system yells at you. Notice that the error gives no clue as to what was done wrong, or the correct format to use.