Hi everyone,

I've been trying to add a site name, gallery name, and enable the user login box for my gallery at www.national8photos.com

Regardless of what theme I use, none of my changes are applying (though I'm not receiving any errors, either.)

I can still upload photos and create new galleries.

Any idea what could be causing this?

I can't reproduce it regarding the gallery name/title, but for the other ones you would have to add the functions to your theme since they are not included by default:
http://www.zenphoto.org/documentation/functions/_template-functions.php.html#functiongetMainSiteName
http://www.zenphoto.org/documentation/functions/_template-functions.php.html#functiongetMainSiteURL
http://www.zenphoto.org/documentation/plugins/_plugins---user_logout.php.html

Ahh, this is all making much more sense now. Thanks.