Mesh placed by color (error in script)

Hi,

I am trying to place 4 different meshes or geometries on different colors on a surface. 

I allready have a script in grasshopper but somehow there is somewhere an error. The meshes are not placed and visible on the surface.

I don't know where the problem is. 

Could somebody have a look at it and help me to find the error?

Thanks a lot!