No, my confidence in office holder's competency was not shaken when Vice President Joe Biden, DNC Chairwoman Debbie Wasserman Schultz and Minneapolis Mayor R.T. Rybak all placed calls to the wrong man while intending to reach the Boston's mayor because errors of this nature have little relevance to the political competence of those who erred. There are many brilliant people who are competent in their field who lack skills in other spheres of activity. Isaac Newton, for example, was very absent minded and would walk off sometimes not even dressed appropriately.
I still have confidence in office holders. Dialing a wrong number is not a big deal. It has nothing to do with the quality of performance by the office holders. They should be judged on their actions of consequence, not on trivial foolishness. A wrong number is a small blip.