Typically these situations are best dealt with effective communication skills. I like to do the following:
1. Listen the person and their problem.
2. Restate what you heard from the other person.
3. If you are asking them a question frame the question, if they still do not understand re-frame the question.
As a last resort if the person is toxic to your project(using candor in your project), ask to have them replaced (the sooner you can do this the better).
Below is a 9 minute video on How to Deal with Difficult People at Work
More blogs about this topic:
More blogs about this topic:
http://www.confidencecenter.com/art12.htm
http://stress.about.com/od/relationships/ht/difficult.htm
http://www.how2dealwithdifficultpeople.com/coping-with-difficult-people