CurveClosestObjects problem

Hi all,

Please help me with this issue.
Why do I get a:
“Runtime error (TypeErrorException): Parameter must be a Guid or string representing a Guid”
in the rs.CurveClosestObjects section?

text_min = is a list of values (ex 25.5, 30, 45.3)
pts = is a list of points
srf = is a surface that intersects with pts
Values in text_min correspond to the points in pts

for i in text_min:
    if i == min(text_min): # Finding lowest value in list 
    else: # Adding all points in other list except the one found from index above.

if len(index_low) == 1:
    line_dir = Geometry.Line(rs.PointCoordinates(pts[index_low[0]]),directionMin[index_low[0]],100)
    line_pull_r = Geometry.Curve.PullToBrepFace(Geometry.Line.ToNurbsCurve(line_dir),rs.coercesurface(srf),0.1)
    line_extend = Geometry.Curve.ExtendOnSurface(line_pull_r[0],Geometry.CurveEnd.Both,rs.coercesurface(srf))

    print "to many in list"

print rs.CurveClosestObject(line_extend,pts_exept)

I’m trying to get the point that is closest to the curve. But mayby CurveClosestObject doesn’t work with points?
there is a function in Grasshopper that does the work (curve nearest object) but I would like to stay in rhinoscriptsyntax if possible.

Any help is much appreciated!
Thanks in advance

You can call the RhinoCommon method it wraps, to directly operate on geometry objects (i.e. not guids):