Another -- MS Office Question

I am using COM to save data to an Excel spreadsheet.

The program works fine when I test it  etc (Excel 03 / Excel 07).

A user is having a problem with (Win7 /Excel 2010). When the data is passed over Excel is not formatting it correctly (it does not recognize date / time fields).

I do not have access to Excel 2010. Would this be a setup issue on the Excel 2010 side? 

Thanks!

Mike