It appears that you are not running Game Crusade on the site you linked to.
As for the errors - the theme is 4+ years old, was developed for WordPress 2, and was released before the Vertex framework was developed; unfortunately, pre-framework releases can no longer be updated due to significant changes in how WordPress works. I would suggest looking at more recent releases to see if there's something newer that you can be happy updating to. The first Vertex release was Paradigm Shift, and the first responsive release was Business Response. I personally recommend not using anything older than Business Response, but that is mainly because the pre-responsive releases that use Vertex will need to be patched with the
Vertex Upgrade Patch before they are fully compatible with the latest version of WordPress.
If you are looking for a good "gaming" theme, "Gamers" is fairly recent and runs the responsive version of the framework; it is also fully compatible with the latest version of WP.