#1 - 2013/01/16 10:21:00 AMI wrangled whole morning and now it all works. Here is how I managed to do it.
1. Go to your Account Summary and click on Diablo 3 game. It should open a new page.
On the bottom right you will see "Public Test Realm" section. Click "Download the game PTR client".
2. It will take you to another page where you can download. Just press Windows "icon". However, default client you will download is enUS. I downloaded enGB. You can change that by clicking "Change" link and selecting "English (EU)" instead of "English (US).
This may be the reason why many people can't login, because they downloaded enUS client. Maybe not. Try following steps first if you have enUS client, maybe it will work. If not, try with enGB.
Pictures on how to download PTR client:
1. Diablo 3 Game Summary PTR Link: http://i.imgur.com/EXc3c.jpg
2. Change PTR Client Version: http://i.imgur.com/Y9QMy.jpg
3. Select and Save: http://i.imgur.com/D5guy.jpg
4. Download: http://i.imgur.com/kWxQ9.jpg
5. Install the Client wherever you want on HDD.
1. Start the 1.0.6 version of Diablo
2. On login screen go to "Options" - Account and select "The Americas" instead of Europe.
2a. You should see down on the login screen "Region: The Americas" instead of "Europe".
3. Login with your u/p.
4. Create a lvl1 Character (any class, any name).
5. Go to "Options" - Account and switch back to Europe. Accept.
7. Start the PTR client and go to Options - Account and change language from English (British) to English. Click accept. Diablo 3 may crash. Doesn't matter, change is accepted.
7a. Login. If Error 12 pops up, change your password for that account.
8. When you login you will see lvl1 char and in upper right corner option to copy the characters to PTR.
9. Select "Copy from: Europe" and press Copy.
10. Wait a bit and game will kick you out to login screen.
11. Login again and you will be on PTR with all your chars from 1.0.6
12. GL HF
I can try answering any questions you might have.
Also, a good way to see if you are on the right track is to click "Patch Notes" in the PTR launcher. It should display full 1.0.7 notes.
EDIT: Some people have trouble "creating" their PTR account. Included few simple steps to download the proper client.
NOTE: You can transfer your characters every 72 hours. If you try earlier you will get Error 39500.