Error evaluating 'OpenFcn' callback of Virtual Reality Sink Block - not enough input arguments

Hi. I am running MATLAB 2017, academic license. I wish to animate some project that I am working on using the Simulink 3d animation.

However, when I double-click the the VR Sink block, I get the popup message

Error evaluating 'OpenFcn' callback of Virtual Reality Sink Block (mask)
not enough input arguments

When I try the command vredit I receive the the error-prompt

Error using vr.edit/createCanvases (line 2610)
  Not enough input arguments.

Error in vr.edit/init (line 2570)
    createCanvases(obj);

Error in vr.edit (line 181)
    init(obj, fname);

Error in vredit (line 22)
  vr.edit(get(ww, 'FileName'));

Help is greatly appreciated. By the way, I can open the loader-gui for an empty VR-sink, but I cannot create a new world and if I point to an already existing wrl file, the same prompt shows up when I double-click it again. Also I can simulate the Simulink diagram, including the VR-block, but I get no access to the 3D-world viewer / editor.

[Ronny Landsverk]

I think the problem was a second-hand toolbox, insisting to be installed in the matlabroot toolbox directory - and hence was able to manipulate some file in the 3D animation toolbox. Or perhaps I did this myself, thinking that I changed a file belonging to the second-hand toolbox. Anyway, I re-installed MATLAB and the problem disappeared.