Doesn't the local host run with my permissions and not ASPNET or Network? I went ahead and followed the KB article and gave permissions to everything in the solution and still no luck.
I noticed this started happening after I checked my controls into TFS. Does anyone have any ideas?
if it started happening after checkin, you might have your Chart_*.png files marked read-only, and you'll need to clear the readonly flag on these files so they can be overwritten by the chart.
if you can avoid having the image files under source control, that would be ideal.