While previous versions of App-V targeted a single instance implementation, the new infrastructure servers for an App-V 5 native deployment are designed to be scaled out and to be diverged across separate machines. The services for Management, Publishing and Reporting are based on IIS, also Streaming can be done from a web site. App-V’s Services uses different ports for all these services – but what if you only want to use a single port, like 80?
The installation of the App-V Management Server 4.5.x on a Windows Server 2008/2008R2 occasionally fails with an “The installation programm was unable to create the required IIS virtual directory: Error 25120″
The most likely cause for this is that the “IIS Management Scripts and Tools” and/or the “IIS 6 Management Compatibility” role features are not installed. This has been discussed and confirmed several times, like at BallBlog, SystemCenterCentral, the App-V forum on Technet, Miito’s Blog and other sources (like here).
Another potential cause, that obviously is not so common, is a missing “Default Web Site” in IIS…