I just downloaded the trial version of Cells and tried to run the report card demo. There is a page error on the default page because a couple of links are not valid. The big problem is when I click the button to generate the spreadsheet I get an exception indicating the Response.Redirect can't be performed because the HTTPHeaders have already been sent.
I commented out the check in the Page_Load handler to just display the sheet and that works, but I would really like to know what is causing the redirect issue. I guess you should have someone put up a debugged set of samples for VS 2005 & .NET 2.0.