Hello folks!
First of all, thanks for a really cool gallery software!
I have been attempting to integrate it into my site by creating a new theme, but am having difficulty getting the Ratings to work correctly. Perhaps it is a css issue... not sure at this point, as I have tried several approaches to no avail.
For some reason, I can get the Star background image to appear, but :hover appears.
Please view: http://www.wildgates.com/gallery/index.php?album=garden-art&page=1
to better understand what I am trying to explain.
Thank you in advance for your help!

The CSS for this is all in the rating.css file in the ../zp-core/plugins/ratings folder. You can check to see if you have a conflict with any of your theme CSS. (Also check to be sure that css file exists on your installation.)

Yes. I thought of that as well, completely stripping-out anything within my CSS that could potentially cause the problem. Didn't help...
If the mouse is hovered over the rating area, one stage of the alt_star.png appears, but not the other two stages(e.g. before a rating is submitted or after).
Any other ideas?

You should probably make sure that the ratings work in the standard theme just to be sure it really is a conflict with your theme.

They appear to work in the standard theme. I have the installation in a folder called "gallery" - do I need to make a change in the "background: url(alt_star.png)" in the rating.css file? Although... the script apparently has located the alt_star.png since I can obtain one behavior out of it upon hovering...

You will just have to figure out what in your theme/css is causing the problem.