When you say web platform components which programs / features are you refering? For this post I'll assume you are trying to install IIS components but if that is not the case let me know.
Are you able to install IIS components using the instructions on this webpage?
http://learn.iis.net/page.aspx/28/installing-iis-70-on-windows-vista/
If you are not then there is a problem with your Windows install. You can try to get more data out of the log file located at:
C:\Windows\Logs\CBS\CBS.log
It should have some information on why IIS components are failing to install.
If you are able to install the IIS components outside of WebPI then it is an error in WebPI in which case the WebPI log files would be helpful.
Thanks,
Andrew