I suspect I know the answer to this problem in a relative way, but I thought I would throw it out there and see if anyone can assist anyway.
I have a site that I maintain (http://www.row.org) where I use Simple Facebook Connect to display a fan box and I've added the like option to all my posts. The plugin works great and I am glad I found this particular tool.
I also use "Improved Include Post" plugin to allow me to create posts and then include those posts by post id on the home landing page to feature them.
Until recently everything has worked great and SFC didn't have any problems showing the like button at the bottom of these included posts. However, at least a couple of updates back, I started to notice an error notice next to the like button when a post was "included" on the front page. The error notice does not show up on the post when I display the actual post, but only if the post has been included and is shown on the front page.
When I click on the error link, here's the exact message I get:
You must specify an "href" attribute to the iframe. Something like <iframe src="http://www.facebook.com/plugins/like.php?href=http%3A%2F%2Fexample.com%2Ffoo%2Fbar.html"></iframe>.
I'm sure this is due in large part to the fact that we are not displaying the complete page on the front page, which may or may not be including all of the code in the header that like button needs to work properly. However, if anyone can give me a better understanding of this problem, or better yet there is some simple fix that will take care of this, I'd appreciate it if you could share that information.