I suspect the issue here is that the robot can't resolve the hostname of your computer. To verify, start up the listener on the robot and the talker on your computer, and then try to rosnode ping the talker from the robot. If it fails, you probably have a network problem. You can then run rosnode info on the talker to see which hostname it's using, and either fix the DNS entries for that hostname, add it to the /etc/hosts file on the robot, or set ROS_IP on your computer before starting the talker.