"When you attempt to install Application Virtualization 4.5 Management Server either through a typical installation option or a custom option that includes App-V Management Web Service on Windows Server 2008 or Windows Server 2008 R2, you may encounter following error: Error 25100. An internal error occurred or Error 25122. The installation program was unable to register the ASP.NET web service extension," revealed Microsoft in KB2212140.
"This issue happens when trying to install App-V MS 4.5 on Server 2008 or ;2008 R2 server that has either .NET 4.0 client profile or full installation of .NET 4.0 framework. This issue occurs because installer attempts to use .NET 4.0 Framework path for registering ASP.NET web extensions. You';ll also see following in Softgrid-server-setup.log file: "[2010-04-22 16:29:57] (1408:3660) Running command ``"C:\Windows\Microsoft.NET\Framework\v4.0.30319\aspnet_regiis.exe" -ir -enable`` | [2010-04-22 16:29:57] (1408:3660) ::CreateProcess error 0x2."
The current workaround is to remove the .NET 4.0 Framework prior to the installation and reinstall the .NET 4.0 framework after installation.