Can someone tell me what's wrong with this script

onClipEvent (mouseDown) {
if (hitTest(_root._xmouse, _root._ymouse, false)) {
_root.3dbutton.tween("_y", 198, 1);
}
}

i keep getting ; expected on the “_root.3dbutton.tween(”_y", 198, 1);" line
im using a tweening prototype.

thanks