Windows Media Player unfrotunately needs a manual download. If you browse for the file on the harddisk and then change your mind, when you hit cancel you get an exception.

h4. Steps to Reproduce
See link to public forum thread for details

h4. Additional Information
http://forum.team-mediaportal.com/mediaportal-1-1-0-rc-3-4-519/installation-error-82942/