Thanks for helping out. Installing ros diamondback with the instructions mentioned here (http://www.ros.org/wiki/diamondback/Installation/OSX) worked. At one point, the rosinstall script could not find yaml for Python 2.6 which I fixed using, port install py26-yaml -- View this message in context: http://ros-users.122217.n3.nabble.com/Problems-installing-ROS-on-Snow-Leopard-tp2455398p2462877.html Sent from the ROS-Users mailing list archive at Nabble.com.