I have the same (or a similar?) issue. Except, I *do* get PART of the button (a few pixels wide but not the whole button).
I'm using WP 3.0.3 and version 2.56 of the plugin - which I'm assuming is up to date, since I installed via admin panel.
I even tried updating my template manually vs letting the plugin insert the code itself, with no change. I'm only displaying it on single pages, not sure if that makes a difference.
Website here, if you'd like to take a look: http://waitingforfairies.com