Excel Interop with older versions of Excel

Question

I have written an application that employs excel to produce a report. This works fine when used on a system with Excel XP or Excel 2003 installed but dies when run on a system with an earlier version installed. This is a bit of a problem as I cannot guarantee that Excel 2000 will NOT be installed on systems running this application. Does anyone know of an alternative that I could employ for those systems where Excel 2000 is installed? Many thanks, Chris