I believe you have to catch the event. I told Chris this but I don't know if he ever relayed the message to you.
Try something like:
PHP Code:
function onCreated() {
this.catchEvent(findplayer("salesman"), "onNickChanges", "onNickChanged");
}
function onNickChanged(pl, old, new) {
echo(pl.account @ "'s old name: " @ old @ " new name: " @ new);
}