SpreadSheet::WriteExcel has a section on modules you can use to read excel. SpreadSheet::ParseExcel is fairly recent so it might work. Otherwise, if you have excel 2007, you can always export the sheet as CSV and use Text::xSV or something similar to read it.

update: in a pinch, it might be worth checking out the data in the file. Since it's XML it should be more readable (once uncompressed) than the previous formats. Note that I have zero experience with office 2007 formats, so I might be talking complete bollocks. :-)