#1 - June 13, 2013, 8:13 p.m.
I have not changed any settings or modified the install in any way whatsoever (no addons, etc). I just downloaded the PTR client from the website, waited for it to download and apply the few gigs of data it needed, and hit the big red PLAY button.
After it gave me the error the first time, I exited the game and waited a few minutes, then restarted. It brought up the launcher first of course, and after checking for updates it said that my game is up to date. I tried again, and got the Error #107 again.
Is there something else that I need to do to get the PTR to work?