I normally use 64-Bit clients but they seem to be broken (both PTS and Live EU).
Using the Elder Scrolls Online Launcher (not something I normally use to access the Game) you press the PLAY button and nothing happens!
This is true for Live EU and PTS.
BTW the download seemed to fail and I had to run a rebuild and that also failed. When I restatred the Launcher it seemed to be OK except that the PLAY Button did nothing at all.