I am following this tutorial: https://www.clearpathrobotics.com/assets/guides/ros/Drive%20a%20Husky.html
Running this:

$roslaunch husky_gazebo husky_empty_world.launch

gives me the following error message:

... logging to /home/viki/.ros/log/e4fa538c-ff94-11e6-a4c2-080027b46cdd/roslaunch-c3po-3773.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.

Traceback (most recent call last):
  File "/opt/ros/indigo/share/xacro/xacro.py", line 60, in <module>
    xacro.main()
  File "/opt/ros/indigo/lib/python2.7/dist-packages/xacro/__init__.py", line 662, in main
    eval_self_contained(doc)
  File "/opt/ros/indigo/lib/python2.7/dist-packages/xacro/__init__.py", line 597, in eval_self_contained
    eval_all(doc.documentElement, macros, symbols)
  File "/opt/ros/indigo/lib/python2.7/dist-packages/xacro/__init__.py", line 533, in eval_all
    eval_all(body, macros, scoped)
  File "/opt/ros/indigo/lib/python2.7/dist-packages/xacro/__init__.py", line 573, in eval_all
    eval_all(cloned, macros, symbols)
  File "/opt/ros/indigo/lib/python2.7/dist-packages/xacro/__init__.py", line 533, in eval_all
    eval_all(body, macros, scoped)
  File "/opt/ros/indigo/lib/python2.7/dist-packages/xacro/__init__.py", line 512, in eval_all
    (str(name), str(node.tagName)))
xacro.XacroException: Invalid parameter "topic" while expanding macro "sick_lms1xx"
while processing /opt/ros/indigo/share/husky_gazebo/launch/spawn_husky.launch:
Invalid <param> tag: Cannot load command parameter [robot_description]: command [/opt/ros/indigo/share/xacro/xacro.py '/opt/ros/indigo/share/husky_gazebo/urdf/description.gazebo.xacro'     laser_enabled:=true     ur5_enabled:=false     kinect_enabled:=false     ] returned with code [1]. 

Param xml is <param command="$(find xacro)/xacro.py '$(arg husky_gazebo_description)'     laser_enabled:=$(arg laser_enabled)    ur5_enabled:=$(arg ur5_enabled)     kinect_enabled:=$(arg kinect_enabled)  " name="robot_description"/>
The traceback for the exception was written to the log file

and when I did this:

roslaunch husky_viz view_robot.launch

I get this:

... logging to /home/viki/.ros/log/4615235e-ff95-11e6-8bef-080027b46cdd/roslaunch-c3po-7396.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://c3po:34708/

SUMMARY
========

PARAMETERS
 * /rosdistro: indigo
 * /rosversion: 1.11.8

NODES
  /
    rviz (rviz/rviz)

auto-starting new master
process[master]: started with pid [7408]
ROS_MASTER_URI=http://localhost:11311

setting /run_id to 4615235e-ff95-11e6-8bef-080027b46cdd
process[rosout-1]: started with pid [7421]
started core service [/rosout]
process[rviz-2]: started with pid [7438]
[ INFO] [1488492728.382519122]: rviz version 1.11.3
[ INFO] [1488492728.382848996]: compiled against OGRE version 1.8.1 (Byatis)
libGL error: pci id for fd 24: 80ee:beef, driver (null)
OpenGL Warning: glFlushVertexArrayRangeNV not found in mesa table
OpenGL Warning: glVertexArrayRangeNV not found in mesa table
OpenGL Warning: glCombinerInputNV not found in mesa table
OpenGL Warning: glCombinerOutputNV not found in mesa table
OpenGL Warning: glCombinerParameterfNV not found in mesa table
OpenGL Warning: glCombinerParameterfvNV not found in mesa table
OpenGL Warning: glCombinerParameteriNV not found in mesa table
OpenGL Warning: glCombinerParameterivNV not found in mesa table
OpenGL Warning: glFinalCombinerInputNV not found in mesa table
OpenGL Warning: glGetCombinerInputParameterfvNV not found in mesa table
OpenGL Warning: glGetCombinerInputParameterivNV not found in mesa table
OpenGL Warning: glGetCombinerOutputParameterfvNV not found in mesa table
OpenGL Warning: glGetCombinerOutputParameterivNV not found in mesa table
OpenGL Warning: glGetFinalCombinerInputParameterfvNV not found in mesa table
OpenGL Warning: glGetFinalCombinerInputParameterivNV not found in mesa table
OpenGL Warning: glDeleteFencesNV not found in mesa table
OpenGL Warning: glFinishFenceNV not found in mesa table
OpenGL Warning: glGenFencesNV not found in mesa table
OpenGL Warning: glGetFenceivNV not found in mesa table
OpenGL Warning: glIsFenceNV not found in mesa table
OpenGL Warning: glSetFenceNV not found in mesa table
OpenGL Warning: glTestFenceNV not found in mesa table
libGL error: core dri or dri2 extension not found
libGL error: failed to load driver: vboxvideo
[ INFO] [1488492729.461125562]: Stereo is NOT SUPPORTED
[ INFO] [1488492729.462189852]: OpenGl version: 2.1 (GLSL 1.2).
OpenGL Warning: No pincher, please call crStateSetCurrentPointers() in your SPU
[rviz-2] process has died [pid 7438, exit code -11, cmd /opt/ros/indigo/lib/rviz/rviz -d /opt/ros/indigo/share/husky_viz/rviz/robot.rviz __name:=rviz __log:=/home/viki/.ros/log/4615235e-ff95-11e6-8bef-080027b46cdd/rviz-2.log].
log file: /home/viki/.ros/log/4615235e-ff95-11e6-8bef-080027b46cdd/rviz-2*.log

How do I resolve these warnings and erros.

P.S: I am using ROS indigo on 64-bit Ubuntu 14.04 LTS in Virtual Box