I installed FS_15 v1.1 and CL Feature Box RC2 to experiment with. What I found was that the Feature Box does not display the graphics properly. I tried loading the default graphics that came with the plugin, both from the FS_15 theme fbox folder and from the plugin fbox folder. In both cases the graphics just show up as X's.
When I did a view source the path to the graphics was all messed up like this: