I got it to work. Here's what I did:
Change:
ChartFX.GetHTMLTag(Width,Height,"Image"
To:
ChartFX.GetHTMLTag(Width,Height,"Jpeg"
I don't know why it works, but it did.
Chris F.
I don't have any suggestions, but I'm having the same problem. For me, it's starting to fail for users with IE7 as well, but it still works in Firefox. Here's a URL where it's happening: http://www.tqsource.org/prep/data/results.asp?question=1&defaultGraph=true&graph1=true. It definitely is a problem with GetHTMLTag.
Chris F.