Generally the site loads pretty slowly from the UK Though it does load for me eventually without error. This error may be dues to slow loading of site generally.
Also, you also have other plugins running like the nextgen gallery which load other scripts. So it isn’t clear which script is causing the problem.
Does this error occur on any other pages? This page is pretty light on scripts compared to say the home page that has a slider.
I noticed you have added the google button which does add some js.You could try upgrading the theme. We have added this to the core now in our new releases and also improved the way the button script is loaded.