Hi,
the scout robot description scout_v2.xacro
├── LICENSE
├── README.md
├── scout_base
├── scout_description
│ ├── CMakeLists.txt
│ ├── launch
│ │ └── scout_base_description.launch.py
│ ├── meshes
│ │ ├── base_link.dae
│ │ ├── base_link_full.dae
│ │ ├── hokuyo.dae
│ │ ├── wheel_type1.dae
│ │ └── wheel_type2.dae
│ ├── package.xml
│ └── urdf
│ ├── generate_urdf.sh
│ ├── scout_v2.urdf
│ ├── scout_v2.xacro
│ ├── scout_wheel_type1.xacro
│ └── scout_wheel_type2.xacro
└── scout_msgs
links to files /scout_ros2/scout_description/meshes/scout_v2/XXX.dae where the files are actually in /scout_ros2/scout_description/meshes/XXX.dae.
To fix the bug you will have to either change the .xacro to reflect the correct path OR copy the files into the respective directory. Please fix.