Please add error codes here if you have a solution for them.
Error 108 - I believe this is due to an incomplete file having been downloaded. Check the download directory to see if there is a .prt file in there. If so, restart the downloader and allow it to finish.
Launch Night Login
As we’ve unlocked the Diablo III installer early, many people will be ready to log in right when the servers go live at midnight, so we’re going to be closely monitoring the impact on the service. It’s possible we’ll need to adjust the rate at which we’re logging people in to ensure a stable experience, and if we do you may see a delay when attempting to login. Please be aware that a delay of up to 40 seconds is possible while the game attempts to connect you. If your connection doesn’t succeed in 40 seconds, you’ll be presented with an Error 37 message and asked to try again. If you see this error it does in fact mean that you should try again.
"This Battle.net account does not have a Diablo III license attached to it. (Error 12)"
"Battle.net is down for maintenance. Please try again later. (Error 33)"
As we find new error codes and find solutions post them here. Then I will copy and paste your post into this one and delete all other posts in here to keep it clean.