To get a true visual of where the leak is happening put some liquid dish soap and water is a spray bottle, shake it up and spray the regulator until you see bubbles. The bubbles will reveal where the leak is.
I had a leak with my Kegconnection.com Chud regulator. I fixed it by adding a second regulator washer (http://stores.kegconnection.com/Detail.bok?no=410
). Two of them together was my solution.