Facebook – Automatically posting from Tumblr to a Facebook business page (not a personal Facebook wall)

The staff answers your question here:

http://staff.tumblr.com/post/165847841/facebook

The simple answer:

Go to this link -- http://apps.facebook.com/tumblr-feed/ to activate it

I'm having the exact same problem - goes through the approval process fine, but nothing appears on the page. As you say, profile is working fine, just pages. I tried different accounts and browsers, as well as a few tricks, same result. I can only assume it's a bug as the whole Twitter Facebook thing has been shifty this month. One workaround is to use the facebook app Selective Tweets. This will post to pages; however unlike the native twitter app, each tweet you want to go to the facebook page you must end with #fb, hence the whole "Selective" thing. But at least they show up (and the #fb tag won't show on the page).