[Plugin: Post Star Rating] No 2.5 Support?

I’m trying to learn more about this plugin, but the plugin’s homepage is just the designers reel. Can’t find much information about versions.

I tried installing on a 2.5 WordPress just for kicks, I can see the stars and am able to mouseover them, but when I click to choose it does nothing.

Am I correct in assuming that this is a 2.5 WordPress problem?