[Koha] Facing Issue during Installation of KOHA

Hi, I receive an error message on installation of KOHA on WindowsXP saying "Corrupt Installation File". Please find attached the screenshot of the same and someone please help me out in this regard. Also if possible please let me know from where I can get a good copy of the installable. I had downloaded it from http://www.koha.rwjr.com/ Please help me out at the earliest. Thanks, Sai.