I got the message too. I don't know about anyone else but I tried to click on the "get code" button and it leads to a 404 error page.
Someone misspelled the word button in the url and trying to add it gets you redirected to the misspelled 404 page.
Looking it up online leads to a ton of pages on how to use it, how to be logged into your google account... but not much on how to add it to your site.
On page 3 of google search results I found a 3rd party site with a link to the right page. In case anyone else is looking, and until the typo url is fixed, go here [google.com...]
edit: the url is wrong on this page too, where it says "grab a snippet of code". very annoying :P [google.com...]