I get a similar popup box that keeps comming up when I try to close Xolox, it says "Xolox has caused an error in {unknown} and will now close". But the popup box won't stay closed. I have to restart to get rid of it. It mainly happens when there is an upload or download in progress (when I close Xolox). I use Windows ME and have a cable connection. Xolox 1.12