Error in script which copies charts from Excel to PowerPoint

Question

I am attempting to call the below Sub in order to copy given chart to a specified PowerPoint presentation. However, when I run the macro which calls this Sub, the line indic

Answer 1

It looks like the error can be attributed to how VBA handles variables across different references. (In particular, how PPT VBA handles them.) I was able to get the macro to work by actively selecting/copying the charts. I will need to do a little more research to get why variables cause problems, but at least I know how tackle the problem.

Sub copyChart(curSlide As Slide)
    Dim chr as ChartObject
    Set chr = Sheets("CHARTSHEET").ChartObjects(1)  
    Sheets("CHARTSHEET").Select
    ActiveChart.CopyPicture
    curSlide.Shapes.PasteSpecial
End Sub