Import of outlook contacts to live mail via csv file is only partially succesful

I have Windows 7 fully updated and outlook 2007 installed, I want to export my contacts to live mail and follow the export to csv option from outlook. When I upload to live mail I only get a small number of contacts import most of which appear to have no e.mail address? I have tried following the instructions several times with no better success. What am I doing wrong and why does the csv file appear to be corrupt as it does not import successfully?