使用Add-WindowsFeature 照成的问题

I get the failure below..  If I pick the Server 2012 R2 image from 8/15/2014 the same command works fine.

Name[0]: PS C:\Users\demouser> Add-WindowsFeature "Web-Server" -IncludeAllSubFeature -IncludeManagementTools

Add-WindowsFeature : The request to add or remove features on the specified server failed.

Installation of one or more roles, role services, or features failed.

The source files could not be found.

http://support.microsoft.com/kb/2734782

.NET Framework 3.5 安装错误：0x800F0906、0x800F081F、0x800F0907