I installed VSlab and it seems everything is fine, but when I open one example of it, Graph.fsx:

it gives the following the following errors:
val gv : VSLab.Chart.GraphControl

Binding session to 'C:\Program Files\University of Pisa\VSLab\VSLabChartPackage.dll'...
System.NullReferenceException: Der Objektverweis wurde nicht auf eine Objektinstanz festgelegt.
bei System.Windows.Forms.Control.get_Controls()
bei VSLab.Viewlet..ctor()
bei VSLab.Chart.GraphControl..ctor()
bei .$FSI_0002._main() in D:\test\Project_vs\Project_vs\Graph1.fsx:Zeile 10.
stopped due to error


#light
// These references are required only for typechecking purposes
// you can skip their evaluation.
#r "ViewletControls.dll"
#r "VSLabFSICore.dll"
#r "VSLabChartPackage.dll"

open VSLab.Chart

let gv = new GraphControl();;

gv.Show();;

gv.ShowProperty();;

gv.Close();;

//////////////////////////////////////////////////

second examle:

#light
// These references are required only for typechecking purposes
// you can skip their evaluation.
#r "ViewletControls.dll"
#r "VSLabFSICore.dll"

open System
open System.Drawing
open System.Windows.Forms

open VSLab

// let's create some viewlet..

// a simple function plotter
let t2 = new plotter()
t2.Show()

...


it gives the error:

D:\test\Project_vs\Project_vs\Tutorial1.fsx(16,14): error FS0039: The type 'plotter' is not defined.

I can not find out plotter is whose member?
anyway this is the example in VSLab. It is a little strange to me.

I really can not find out the reason.
if anyone can give me one hint, I appriciate it very much.