WordPress built-in gallery functionality doesn’t work with theme

I’m stumped with this and I’ve been bashing my head against the wall. I’m migrating an existing blog that made extensive use of the built-in galleries functionality available in WordPress, but for some reason the galleries shortcode doesn’t work with this theme (it works without modification with the default TwentyTen theme as well as most other themes I use, just not this one.) When creating a post that uses gallery shortcode, the code is visible in the editor but there’s simply nothing at all in the output on the website. I’m assuming that the galleries plugin that comes with the theme is overriding this somehow, so how would I disable it completely and just continue using what’s built into WordPress?