Enabling buttons through MovieClip.Prototype

I’m trying to make this script work which has a function to enable buttons.

// This script is on a seperate layer frame:
// webnav, iden, adv, mult are instances of MCs

btns = [webnav, iden, adv, mult];
MovieClip.prototype.enableBtns = function(btns) {
for (i=0; i<btns.length; i++) {
btns*.enabled = true;
}
}

// This is on the MC itself
//partial code …within onClipEvent handler

_root.navbtns_mc.webnav.onRelease = function() {
_root.navbtns_mc.webnav.enabled = false;
enableBtns(_root.btns);
}

The buttons disable but just don’t enable again when other buttons are clicked.

The button instances are on the path: _root.navbtns_mc.