When you attempt to install the Application Virtualization 4.5 Management Server either through a typical installation option or a custom option that includes the Application Virtualization Management Web Service on Windows Server 2008 or Windows Server 2008 R2, you may encounter the following error:
Error 25100. An internal error occurred.
Error 25122. The installation program was unable to register the ASP.NET web service extension.
This issue happens when trying to install the Application Virtualization Management Service version 4.5 on a Windows Server 2008 or Windows Server 2008 R2 server that has either the .NET 4.0 client profile or full installation of the .NET 4.0 framework. This issue occurs because the installer attempts to use the .NET 4.0 Framework path for registering the ASP.NET web extensions.
You will also see the following in the Softgrid-server-setup.log file:
The current workaround is to remove the .NET 4.0 Framework prior to the installation and reinstall the .NET 4.0 framework after installation.
Microsoft has confirmed this to be a problem with the 4.5, 4.5SP1, and 4.5SP2 installer.