How to fix that failed to launch empty_world.launch on Hydro?

edit

I use ROS Hydro with ubuntu 12.04.

I run:

sam@sam:~$ roslaunch gazebo_ros empty_world.launch 
... logging to /home/sam/.ros/log/2a9a2cdc-e7d8-11e3-9bc9-20cf30a23845/roslaunch-sam-6178.log
Checking log directory for disk usage. This may take awhile.
Press Ctrl-C to interrupt
Done checking log file disk usage. Usage is <1GB.

started roslaunch server http://sam:55890/

SUMMARY
========

PARAMETERS
 * /rosdistro
 * /rosversion
 * /use_sim_time

NODES
  /
    gazebo (gazebo_ros/gzserver)
    gazebo_gui (gazebo_ros/gzclient)

ROS_MASTER_URI=http://localhost:11311

core service [/rosout] found
process[gazebo-1]: started with pid [6196]
process[gazebo_gui-2]: started with pid [6201]
Gazebo multi-robot simulator, version 1.9.5
Copyright (C) 2014 Open Source Robotics Foundation.
Released under the Apache 2 License.
http://gazebosim.org

Gazebo multi-robot simulator, version 1.9.5
Copyright (C) 2014 Open Source Robotics Foundation.
Released under the Apache 2 License.
http://gazebosim.org

Msg Waiting for master.terminate called after throwing an instance of 'std::bad_alloc'
  what():  std::bad_alloc
Aborted (core dumped)
[gazebo-1] process has died [pid 6196, exit code 134, cmd /opt/ros/hydro/lib/gazebo_ros/gzserver worlds/empty.world __name:=gazebo __log:=/home/sam/.ros/log/2a9a2cdc-e7d8-11e3-9bc9-20cf30a23845/gazebo-1.log].
log file: /home/sam/.ros/log/2a9a2cdc-e7d8-11e3-9bc9-20cf30a23845/gazebo-1*.log

How to solve it?

Thank you~