error 2503 when installing itune to win8

Hi,

After downloading the itune from the page and clicking for installation, just before the installation finish,

I am getting a msg saying:

'the installer has encountered an unexpected error installing this package. this may indicate a prolem with this package, The error code is 2503"

So HOW can I install itune to Win8 Laptop?

Pls help,

Thank you!