I had a really difficult time getting this to work but my steps were:
*Open the live broadcast and be merry with sign in page (even after signed in and accepted the permission)
*Long press back key so message doesn't pop up, then press settings
*In settings you'll need to add a new account (even if your YT Gmail address is present). My G+ page and YouTube accounts are separate yet under the same Gmail address. YT/Google still haven't merged old YT accounts with G+ pages which is causing issues like this. So, press account and then add account.
*Now you need to visit your G+ page on desktop and press your picture icon in the top right and press the settings button
*Scroll down to “Third-party tools” and click on “Set up password”. This process will let you have a unique username and password for apps that want to interact with your Google account (YouTube is still a Google service), without having access to your main Google credentials. You will get a weird version of your Google account's name “xxx-0000@pages.plusgoogle.com”.
*Now add the email address and the password you just setup in the accounts addition page of the YT live broadcast setup. This should now add your YT account and you can live stream.
Further notes
http://www.phonearena.com/news/Cant-...-do-it_id75671