in the tf and time tutorial there is a line now = rospy.Time.now() but it crashes every time I run it. the error is [listener-5] process has died [pid 6449, exit code 1]. log files: /home/ringo/.ros/log/df877bf2-910c-11e0-bc06-080027911c3f/listener-5*.log now = rospy.get_rostime() crashes as well now = rospy.Time(0) works ok. am I missing something? Ringo