有关将图表导出到PowerPoint的代码的运行时错误91

Question

我正在尝试将图表从Excel导出到PowerPoint，但执行时显示错误91，提示“对象变量或未设置块变量”

我已经进行了研究，没有找到任何可以帮助我的东西。这是代码。

Sub ExportChartstoPowerPoint()
Dim PPApp As Object
Dim chr
Set PPApp = CreateObject("PowerPoint.Application")
PPApp.Presentations.Add
PPApp.ActiveWindow.ViewType = ppViewSlide
For Each chr In Sheets("CPIT Overview").ChartObjects
    PPApp.ActivePresentation.Slides.Add PPApp.ActivePresentation.Slides.Count + 1, ppLayoutBlank
    PPApp.ActiveWindow.View.GotoSlide PPApp.ActivePresentation.Slides.Count
    chr.Select
    ActiveChart.CopyPicture Appearance:=xlScreen, Size:=xlScreen, Format:=xlPicture
    PPApp.ActiveWindow.View.Paste
    PPApp.ActiveWindow.Selection.ShapeRange.Align msoAlignCenters, True
    PPApp.ActiveWindow.Selection.ShapeRange.Align msoAlignMiddles, True
Next chr
PPApp.Visible = True
End Sub

错误在ActiveChart.CopyPicture Appearance:=xlScreen, Size:=xlScreen, Format:=xlPicture行