facebook "like" button gone

[AGN03]

<a href="http://WWW.ultimateponycars.com" target="_blank">WWW.ultimateponycars.com</a>
My Facebook "like" button has been functioning properly for quite some time and now all of a sudden its gone. Literally not there anymore. I checked all the settings and it looks good.
Any ideas? I'm completely lost.
Thanks in advance.

[Lynne]

Since Unregistered Users cannot view your forum, there is no way for Facebook to keep track of which threads are liked or not. when did you make it so unregistered users couldn't view your forum?

[AGN03]

I think you just solved my problem. Is there any way to not let unregistered users see sections and still retain the like button?
I have a company that asked me to make the boards private.