[Javascript Application] Error: syntax error when using Firefox

Hi, I have up until yesterday started to receive a small error box on my screen when i load up my site using firefox 17.01

i have to click the ‘OK’ box at least 5 or 6 times before it goes away and my site loads fine after this. however, every time i navigate to a different page or post, the same thing happens, after which it loads ok

this doesnt happen in chrome or IE, i’m baffled, can anybody help?

my site: http://artbyherbie.com

does anybody get the same issue?
thanks