Invalid <param> tag

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I am trying to modify hector_quadrotor in gazebo. because I am quite new to ROS and Gazebo while processing roslaunch hector_quadrotor_gazebo spawn_quadrotor_with_kinect.launch which exists in the original packages i failed.it shows following error:

in file: /home/ayatoshi/hector_quadrotor_tutorial/src/hector_quadrotor/hector_quadrotor_description/urdf/quadrotor_with_kinect.gazebo.xacro
while processing /home/ayatoshi/hector_quadrotor_tutorial/src/hector_quadrotor/hector_quadrotor_gazebo/launch/spawn_quadrotor.launch:
Invalid <param> tag: Cannot load command parameter [robot_description]: command [/opt/ros/kinetic/lib/xacro/xacro '/home/ayatoshi/hector_quadrotor_tutorial/src/hector_quadrotor/hector_quadrotor_description/urdf/quadrotor_with_kinect.gazebo.xacro' base_link_frame:=/base_link world_frame:=world] returned with code [2]. 
Param xml is <param command="$(find xacro)/xacro '$(arg model)' base_link_frame:=$(arg base_link_frame) world_frame:=$(arg world_frame)" name="robot_description"/>
The traceback for the exception was written to the log file

i dont know how to solve the problem Can you give me some information about how to solve the problem? thanks a lot. here is the spawn_quadrotor_with_kinect.launch：

<?xml version="1.0"?>
<launch>
   <arg name="name" default="quadrotor"/>
   <arg name="tf_prefix" default="$(optenv ROS_NAMESPACE)"/>
   <arg name="x" default="0.0"/>
   <arg name="y" default="0.0"/>
   <arg name="z" default="0.3"/>

   <arg name="use_ground_truth_for_tf" default="true"/>
   <arg name="use_ground_truth_for_control" default="true"/>
   <arg name="use_pose_estimation" if="$(arg use_ground_truth_for_control)" default="false"/>
   <arg name="use_pose_estimation" unless="$(arg use_ground_truth_for_control)" default="true"/>

   <include file="$(find hector_quadrotor_gazebo)/launch/spawn_quadrotor.launch">
     <arg name="name" default="$(arg name)"/>
     <arg name="model" value="$(find hector_quadrotor_description)/urdf/quadrotor_with_kinect.gazebo.xacro"/>
     <arg name="tf_prefix" default="$(arg tf_prefix)"/>
     <arg name="x" default="$(arg x)"/>
     <arg name="y" default="$(arg y)"/>
     <arg name="z" default="$(arg z)"/>   
     <arg name="use_ground_truth_for_tf" value="$(arg use_ground_truth_for_tf)"/>
     <arg name="use_ground_truth_for_control" value="$(arg use_ground_truth_for_control)"/>
     <arg name="use_pose_estimation" value="$(arg use_pose_estimation)"/>
   </include>

</launch>`