Janet,
I just commented on the home page, and it worked for me. I'm leaving the comment there, but feel free to hide it so others don't see (or I can delete it when you respond to this).
The post did show up in my Wall as expected, of course, that was with the "Post to Wall" box checked. The image is pulling the Facebook affiliate image, which I believe we mentioned how to add an Open Graph tag to pull your logo or other image in another post.
So.. hope that helps let you know that it is working. However, if it's not for you, we'd recommend from a different account (to test) or on a different page of your site. Posting multiple times from the same page has different effects for the priority that FB will show those posts in your wall. It's possible multiple posts just cause the newer ones to simply get shoved down or not shown at all to prevent multiple posts from looking spammy.
Good luck,
Alex