Macro for custom property thru task schedular

Dear all,

I am trying to run the following macro thru task schedular to add custom properties to the bulk of assembly files in a particular folder. But i am getting error as "OpenErr 1    Assem1.SLDASM   Error 91 (Object variable or With block variable not set) in procedure main of Module Macro11". It is working fine for the part files not the assembly files. Could anyone help? please...

Thanks,

Pals

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Sub main()
Dim swApp As SldWorks.SldWorks
Dim Part As SldWorks.ModelDoc2
Dim lErr As Long
Dim lWarn As Long
Dim FileNumber As Long
Dim sFile As String
Dim sPath As String

Const flogfile As String = "C:\10 PROPERTY MACRO  - BULK TRIAL\assy file\logfile.txt"
   On Error GoTo main_Error

Set swApp = CreateObject("SldWorks.application")
FileNumber = FreeFile
sPath = "C:\10 PROPERTY MACRO  - BULK TRIAL\assy file\"
sFile = Dir(sPath & "*.SLDASM", vbNormal)
Do While sFile <> ""
    Set Part = swApp.OpenDocSilent(sPath & sFile, swDocPART, lErr)
    Dim myModelView As Object
    Set myModelView = Part.ActiveView
    myModelView.FrameState = swWindowState_e.swWindowMaximized

    If lErr = 0 Then
        Part.ClearSelection2 True
        Part.DeleteAllRelations
        Part.AddRelation """Num"" = Assembly.Extension.CustomPropertyManager("""").Set(""number"", Left(Assembly.GetTitle, 8))"
        Part.AddRelation """Prt"" = Assembly.Extension.CustomPropertyManager("""").Set(""partno"", Left(Assembly.GetTitle, 12))"
        Part.AddRelation """Dwg"" = Assembly.Extension.CustomPropertyManager("""").Set(""dwgno"", Left(Assembly.GetTitle, 8))"
       
        Part.Save3 swSaveAsOptions_Silent, lErr, lWarn
        Open flogfile For Append As #FileNumber
        Print #FileNumber, "saveErr " & lErr & vbTab & lWarn & vbTab & sFile
        Close #FileNumber
       
        swApp.CloseDoc sFile
    Else
        Open flogfile For Append As #FileNumber
        Print #FileNumber, "OpenErr " & lErr & vbTab & sFile
        Close #FileNumber
    End If
    swApp.CloseDoc sFile
   
    sFile = Dir
Loop
main_exit:
    On Error GoTo 0
    swApp.CloseAllDocuments True
    swApp.ExitApp
    Exit Sub

main_Error:

    Open flogfile For Append As #FileNumber
    Print #FileNumber, "OpenErr " & lErr & vbTab & sFile & "   Error " & Err.Number & " (" & Err.Description & ") in procedure main of Module Macro11"

    Close #FileNumber
    GoTo main_exit
End Sub

SolidworksApi macros