It doesn't seem like you have any URLs defined for the menu items to go to. I'm not sure where the script came from, but they probably have instructions about where to put the target URLs in your code. I'm guessing:
Code:
stm_aix("p0i5","p0i0",[0,"Contact Us"]);
i.e.
Code:
stm_aix("p0i5","p0i0",["contact_us.html","Contact Us"]);
or somewhere in that third argument array. There may be other issues with the first two arguments, like if they are supposed to be unique, however I'm not seeing any Javascript errors.