I am getting this error:

Runtime Error '2116157058 (81de017e)':
Method "Add" of object "ChartObjects" failed

This happens when I use my macro code:
Set cht = ActiveSheet.ChartObjects.Add(0, 0, rng.Width + 10, rng.Height + 10)

And it even happens when I use the Microsoft Help example code below:

Dim ch As ChartObject
Set ch = Worksheets("sheet1").ChartObjects.Add(100, 30, 400, 250)
ch.Chart.ChartWizard source:=Worksheets("sheet1").Range("a1:a20"), _
gallery:=xlLine, title:="New Chart"

Does anybody know what could be causing this error, and how I can fix it?