not load file or assembly 'System.Windows, Version=2.0.5.0...'

if you get this error, it's because Sliverlight assembly is not in GAC. Do this to fix:


cd C:Program FilesMicrosoft Silverlight4.0.50524.0
gacutil -i System.Core.dll
gacutil -i system.dll
gacutil -i system.net.dll
gacutil -i system.xml.dll
gacutil -i System.Runtime.Serialization.dll


check out what other people said.