The target of update() is supposed to be the image object... Dang, I wonder who's my target?

One minute it says it's not preceded by an object, the next it says it's not a function.
Sometimes I really don't know what I'm getting, mostly guessing ......

    function reLink() {
        link.reinitLink(encodeURI(lst[ppJ]));
        link.update();
        app.activeDocument.links.everyItem().update();
    }

I have defined the Link, who is the subject of my update()?

var link = selectedFrame.images[0].itemLink;