I am an researching the beta Recommendations Bar plug-in by trying to sample it on my personal blog, however after much tinkering and triple checking the instructions here http://developers.facebook.com/docs/reference/plugins/recommendationsbar/ I have not been able to get past the following error
Given URL is not allowed by the Application configuration.: One or more of the given URLs is not allowed by the Application configuration. It must match one of the Connect or Canvas URLs or domain must be the same as or a subdomain of one of the Application's base domains.
As far as I can tell my app is configured correctly. What am I doing wrong? Here is a page from my personal blog for debugging http://doug.mn/post/16797908185/lowry-uptown-crepes
Try changing
data-href="https://developers.facebook.com/blog/post/559/"
to Your site's URL. Also, did You set App Domain and Website -> Site URL correctly in the Facebook Application Settings panel?