I'm using MenuMaker 1.1 and am having this same problem. I made that change to the file but get the same issue. It didn't fix it. The site is http://www.mominusa.com/ Select from Products menu, add to cart, then go to checkout. Mouse over About Us or Products and it will occur.

I changed that spot of code to ifr=0; I'm assuming that's 'zero' and not a capital 'O'

anyone?