looks like a similar bug FF/IE have with the position "Inside" mode using videototexture, ill re-upload with "infront" so it works on modern browsers properly. the white textures are a problem FF has with loading in assets, you'll need to refresh a couple of times to get rid of them.
Thanks for the report though, i'll see if i can find a work around to the implementation issues FF has with webgl... In general chrome / nodewebkit is the browser that this plugin is doing it's best to support, since the others aren't really as good at keeping up with the standards required, they'll get better with time however.
HOWEVER you did help me find a nice little bug with the loader that parses sprite-sheets, so i fixed that for next version.