Hi Cynthia,
You do not have $w.onReady in the upper scope. it is inside the button4_click_1 function, which defines its own $w to get the button clicked (it is trying to call Object.button4.onReady, and that does not exist). Make sure to close off that function with a curly bracket
export function button4_click_1(event, $w ) {
//Add your code for this event here:
// Runs a query on the “Members” collection
}