Slideshow Gallery CSS Conflict?

I have the slideshow running on two identical sites. The original is on the home page of this sandbox site, using WP 3.1.2 here: https://tkorlando.com/dev_wpha

With some tweaking to the gallery-css.php file I styled everything the way I wanted, no problems.

However, once we migrated the test site files to another domain with a fresh install of WP 3.1.3 we found some styling issues, specifically #fullsize {overflow:hidden;} is completely ignored by the browser as seen here:

https://test.wphistory.org

Does anyone know if it’s specifically a WP version issue? The gallery-css.php file is exactly the same in both sites, and all other settings are identical as far as I can tell. I’ve tried switching to the TwentyTen theme and deactivating all other plugins and no dice. Any suggestions for a fix would be appreciated (my guess is to add that style to the theme CSS, but if anyone has a better idea I’m all ears).

Here’s the full code from the php

#fullsize { position:relative; z-index:1; overflow:hidden; width:<?php echo ((int) $styles['width'] - 0); ?>px; height:<?php echo ((int) $styles['height'] - 0);?>px;

Thanks in advance,
Mary