check to make sure whoever you are sending the message to has the messenger service turned on. All a router will do is make it so you have to be a little more specific about where your sending the msg to (think of a router like a post office)...this .bat file you are creating is actually an easier way of using the net send dos command. So if you wana wana know what your really doing or just do it manually do a start menu>run...>type in "cmd". Then type {net send ?} when the dos cmd promp pops up and go from there.