Many thanks to Ed Blankenship, who pointed out that the XLS file that I had uploaded had a phantom reference to a TFS Server, so when you tried to use it, it would error out: ""TF80068: Team Foundation encountered an error while communicating with the server. Please check your connection and try again."
Bad Gregg! Bad! No Biscuit!
I have re-uploaded the Dashboard-TFS.xls file to the first post, with any references to the TFS Server stripped out. Ed has verified it for me, so you if you want to use this tool, it should work for you.