New ipod installation probs

Just got a new ipod and am trying to download the relevent software but am coming up against a error message during the installation process.

I get a windows installer message saying

The system adminstrators has set policies to prevent this installation

Any ideas what i need to do to get the software installed correctly?

Please keep it simple, its been a long day, i am stuffed with turkey and finding it hard to concentrate

Many thanks

Merry Christmas