PhotoPaint crashes everytime I run this macro

I'm trying to write a macro for Photo Paint, but, since there is no recorder and not much documentation, I'm going by trial and error. The problem I'm having is that PP crashes every time I run this macro and try to close the document without saving the changes. Maybe somebody can take a look at it and detect what I'm doing wrong that causes so many crashes.

Sub IndexSixSimple()

    '-----------------------------------------------------------------------------
    'Index separations with six basic colors in simple form.
    'Macro created by Manuel Rivas. April 2009
    'This macro takes either an RGB or CMYK file and separates it in six primary
    'colors: Black, White, Yellow, Blue, Red and Green
    '-----------------------------------------------------------------------------

    Dim Doc As Document, pal As Palette
    Dim Blk As Color, Wht As Color, Yel As Color, Red As Color, Grn As Color, Blue As Color
    Dim FOpen As String, palpath As String
    Dim cm1 As New ColorMask
    Dim CRed As Channel
    
    Set Doc = ActiveDocument
    
        If Doc Is Nothing Then
        MsgBox "Open File first", vbOKOnly, "There are no open documents"
        FOpen = CorelScriptTools.GetFileBox("Bitmap Files (*.bmp; *.jpg; *.tif; *.cpt; *.psd)|*.bmp; *.jpg; *.tif; *.cpt; *.psd", _
        "Open File")
        End If
        
        If FOpen <> "" Then
        Set Doc = Application.OpenDocument(FOpen)
        Else
            If Doc Is Nothing Then
            Exit Sub
            End If
        End If
    
    Set pal = Palettes.Create("Six Simple", , True)
    palpath = pal.FileName
    
    Set Blk = CreateColorEx(2, 0, 0, 0, 100)
    Set Wht = CreateColorEx(2, 0, 0, 0, 0)
    Set Yel = CreateColorEx(2, 0, 0, 100, 0)
    Set Red = CreateColorEx(2, 0, 100, 100, 0)
    Set Grn = CreateColorEx(2, 100, 0, 100, 0)
    Set Blue = CreateColorEx(2, 100, 28, 0, 0)
    
        With pal
        .AddColor Blk
        .AddColor Wht
        .AddColor Yel
        .AddColor Red
        .AddColor Grn
        .AddColor Blue
        End With
        
    Doc.ConvertToPaletted cdrPaletteCustom, cdrDitherJarvis, 100, , , , , , , , , palpath
        
        With cm1
        .AddColor Red
        .Threshold = 1
        .Inverted = True
        End With
        
    Set CRed = Doc.Channels.AddFromColorMask(cm1, "Red", 100, Red)
    

End Sub