I am trying to download itunes 5 and it says "an error occured while instalation assembly" Can someone help

I am trying to Download itunes 10 , and everytime it keeps saying "an error has occured during the installation of assembly'Microsoft.VC80.CRT.type="win32"version"8.0.50727.4053"publickeyToken=" 1fc8b3b9a1e18e3b".processorArchitecture="amd64"'.Please refer to Help and Support for more information. HRESULT: 0x80070002.