I think facebook fixed it, I'm able to send the link va chat and had a few people test it, So far found a lot of different bugs trying to fix. IE firefox not playing at all. Chromes loader is broken and people have to refresh. But still can't get it working on facebook. No matter what I do When i go into facebook Developers, then go to settings. In the app domains I put in both Dropbox and It's off link with is https://dl.dropboxusercontent.com and still get an error. There only feedback is this.
This must be derived from Canvas URL, Secure Canvas URL, Site URL, Mobile Site URL, Page Tab URL or Secure Page Tab URL. Check and correct the following domains: dl.dropboxusercontent.com
I'm not 100% sure what to do.
(p.s.) it seams that the forms auto notifications are not working right now, that is why it took me a wile to respond.