Hi - I am afraid I need some help

Here is the script I am running for an Addin installation and unfortunately
the Excel object created do not dissapear after putting it to nothing... I am
then obije to kill it and the installation is not done...

Here is my script... the xla file is suposed to be already available...

Set appXL = CreateObject("Excel.Application")
Set objFileToInstall = oFSO.GetFile(objTargetFolder & "\" & file.name)
For Each objAddin In appXL.Application.addins
If objAddin.name = ObjFileToInstall.Name then
If Not objAddin.installed Then
On Error Resume next
objAddin.installed = True
If Err < 0 Then
WScript.Echo " ... " & "Err.description: " & Err.Description
Else
WScript.Echo " ... " & objAddin.name & " installed..."
End If
Else
WScript.Echo " ... " & objAddin.name & " already installed..."
End If
End If
Next
Set appXL = Nothing

Everything run properly except the "objAddin.installed = True" instruction
I have also tried
"appXL.Application.Addins.Adds(objFileToInstall.na me)"
then
"appXL.application.Addins(objFileToInstall.name).i nstalled = true
But not working neither...

Thanks for your help
Alain