There haven't been any recent changes to the Like-Box/JFBCFan module that we're aware of and we keep up on this things pretty well. Just to verify, the URL you are putting into the parameters is:
* A full Facebook URL, like
www.facebook.com/SourceCoast (feel free to try that to see if it works)
* A Facebook Page URL, *not* a Facebook profile URL. The Fan module only works with Facebook Pages, not personal profiles.
Hope that helps, but if it still doesn't work, please let us know the Facebook Page URL you are using and we can investigate further.
Thanks,
Alex