Apps setVisibility crashes with timer

[guyAtAndroid]

I'm trying to write an app that has a button that appears and disappears after some time (similar to the maps' zoom in/out buttons).
My code is as follows:

..
t = new Timer(false);
t.schedule(new TimerTask() {public void run()
{
Log.d("starting disabling buttons", "== here ==");
for (Button b : buttons){
b.setVisibility(View.INVISIBLE);
Log.d("after visibility", "== done ==");
}
}}, 3000);
..

I get the first debug message but not the second. Ideas?

thanks
Guy