Import fails (expects prefab, folder has stl)

[kille19]

Describe the bug
I'm trying to import the fanuc m710ic-70 into my project, but when clicking on import i get:

I have the following folder URDF.zip inside my Asset folder.
Furthermore I did change the path for the mesh files inside the urdf.

I got the urdf from https://github.com/robot-descriptions/fanuc_m710ic_description