Trying to install/enable VoiceOver on a 4th Gen Shuffle, I get "unable to install, error message 1618". Help.

I am having problems installing/enabling Voice/Over on a new 4th Gen iPod Shuffle.

I am using a Windows 7 PC.

Afer I "plug in " the iPod Shuffle, underr Summary, when I select Enable OverVoice, and click on Apply, the dialogue boxes appear to download from Apple Sofware Update "VoiceOver kit for iPod" v.1.4.2, I then click "Next" and "Agree". The VoiceOver Kit software is downloaded, I then click to install, "Yes" etc. Then I get a dialogue box saying "iTunes was unable to install the VoiceOver Kit. An unknown error occurred (1618)". I've tried this several times, and get the same result.

Anyone able to help?