[X4U] Opening XML Spreadsheets

[Mark]

Our (stupid) management application is set up to export data as Excel xml Spreadsheets, openable in Office 2003
I am running Office 2004, NeoOffice, iWork 08, OpenOffice (though VMWare Fusion) and TextMate! Nothing can access this information. I even installed the MS document converter ... but that tells me the file is not valid (i.e. Not 2007)

Any ideas as to how to extract the info? We only have one machine with 2003 on it - don't ask! "They" know best.
I have wasted too much time taking these files and "Save As...", "new name", as type "Excel Spreadsheet"!

Thanks

A very annoyed teacher!