Gazebo doesn't start even though no errors are reported

edit

This is rather weird. Gazebo refuses to start but no errors are reported...

The problem lies somewhere in the URDF file of the robot since commenting it out fixes things:

ROBOT URDF:

<?xml version="1.0" ?>
<!-- =================================================================================== -->
<!-- |    This document was autogenerated by xacro from robot.xacro                    | -->
<!-- |    EDITING THIS FILE BY HAND IS NOT RECOMMENDED                                 | -->
<!-- =================================================================================== -->
<robot name="robot" xmlns:xacro="http://www.ros.org/wiki/xacro">
  <!--This URDF was automatically created by SolidWorks to URDF Exporter! Originally created by Stephen Brawner (brawner@gmail.com) 
     Commit Version: 1.5.1-0-g916b5db  Build Version: 1.5.7152.31018
     For more information, please see http://wiki.ros.org/sw_urdf_exporter -->
  <link name="base_link">
    <inertial>
      <origin rpy="0 0 0" xyz="0.00390777224516517 -0.032446267219719 0.184169550820421"/>
      <mass value="4.20121630268732"/>
      <inertia ixx="0.0149000386129946" ixy="-4.66831001352174E-09" ixz="5.23920338795194E-08" iyy="0.0234359493013497" iyz="0.000771538751024883" izz="0.0286744535302635"/>
    </inertial>
    <visual>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh filename="package://robot/meshes/base_link.STL"/>
      </geometry>
      <material name="">
        <color rgba="0.529411764705882 0.549019607843137 0.549019607843137 1"/>
      </material>
    </visual>
    <collision>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh filename="package://robot/meshes/base_link.STL"/>
      </geometry>
    </collision>
  </link>
  <link name="FL">
    <inertial>
      <origin rpy="0 0 0" xyz="-5.55111512312578E-17 9.10729824887824E-18 -6.93889390390723E-18"/>
      <mass value="0.0615219544751675"/>
      <inertia ixx="5.54433425808419E-05" ixy="-1.45453466603006E-20" ixz="-1.00225538664655E-21" iyy="3.00921775305435E-05" iyz="2.309188417276E-21" izz="3.00921775305435E-05"/>
    </inertial>
    <visual>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh filename="package://robot/meshes/FL.STL"/>
      </geometry>
      <material name="">
        <color rgba="0.298039215686275 0.298039215686275 0.298039215686275 1"/>
      </material>
    </visual>
    <collision>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh filename="package://robot/meshes/FL.STL"/>
      </geometry>
    </collision>
  </link>
  <joint name="FLJ" type="continuous">
    <origin rpy="1.5707963267949 0 0" xyz="-0.162088045105054 0.0440194465480433 -0.0035605397876617"/>
    <parent link="base_link"/>
    <child link="FL"/>
    <axis xyz="-1 0 0"/>
  </joint>
  <link name="FR">
    <inertial>
      <origin rpy="0 0 0" xyz="2.77555756156289E-17 -5.3776427755281E-17 3.46944695195361E-17"/>
      <mass value="0.0615219544751675"/>
      <inertia ixx="5.54433425808419E-05" ixy="-1.73616162087809E-20" ixz="-8.97406720914896E-21" iyy="3.00921775305435E-05" iyz="-2.24902265994014E-21" izz="3.00921775305435E-05"/>
    </inertial>
    <visual>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh filename="package://robot/meshes/FR.STL"/>
      </geometry>
      <material name="">
        <color rgba="0.298039215686275 0.298039215686275 0.298039215686275 1"/>
      </material>
    </visual>
    <collision>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh filename="package://robot/meshes/FR.STL"/>
      </geometry>
    </collision>
  </link>
  <joint name="FRJ" type="continuous">
    <origin rpy="1.5707963267949 0 0" xyz="0.169947769597777 0.0440194465480434 -0 ...