Theme Customizer issue

Hello,

Just installed fresh copy of WordPress 4.1.1. Brand new database and wp-config.php. I cannot get the Theme Customizer to display at all. Initially it would only show a blank white screen. I turned on debug mode, and when I select Appearance -> Customize, or when I click the “Customize” button on the theme, I get the following error:

Fatal error: Call to a member function is_theme_active() on a non-object in /usr/local/www/wordpress/wp-admin/customize.php on line 88

I do have some programming experience, but not with PHP. To my eye, it looks like $wp_customize isn’t getting defined but it’s not clear to me why. Any help would be appreciated.

I have tried, to no avail:
* Loading the Twenty Thirteen and Twenty Fourteen themes
* Enabling/Disabling/Removing plugins
* Firefox for Ubuntu 36.0.4 (no plugins) & Chromium 41.0.2272.76 Ubuntu 14.04 (64-bit)
* Flushing the cache of both browsers and trying again
* Re-downloading tar.gz and actually checking it against the md5 sum before decompressing
* Erasing/overwriting entire WordPress install.
* Dropping and re-creating database

Desktop environment is Ubuntu 14.04 x64, no java or flash installed.

Server environment: (all items on same localhost except MySQL)
* FreeBSD 10.1 (sparc64 on a SunBlade 150)
* nginx 1.6.2
* php-fpm 5.4.38
* mysql-server 5.6.23 (on another FreeBSD 10.1 amd64 machine)

There is no firewall active on either desktop or server. Thanks for the help!

EDIT: Forgot to mention, as far as I’ve tested, the rest of the WordPress install is functioning fine.