qooxdoo's mouse event needs to be initialized with a native event object to get mouse coordinates and other information. Try this:
events.register("mousemove",me.map, function(e){
var qxE = new qx.event.type.Mouse();
qxE.init(e);
console.log("Attempt to make a Qooxdoo mouse position at OpenLayers location", e);
me.mouseoverPopup.placeToMouse(qxE);
return true;
},true);