Karamba Supports

Hi there.

I have hopelessly been trying to define my supports in Karamba, without succes.

It keeps showing me this message:

Solution Exception: Could not find node where support number 0 is attached.

I thought it was an issue with the support plane, so I tried to put every node on the same z-coordinate, run a plane through it and redefine the Plane of Reference. But that doesn't help...

Could anyone help me out please?

(The coloured mesh comes from RhinoVault, I want to redo a structural analysis with Karamba.)