This is a Windows Installer issue, not a Mirra-related problem. Error 4099 occurs when there’s a problem with the Windows Installer on your system. When you begin the Mirra installation, the Installer checks to see if .NET Framework 1.1 must be installed.
If there’s a problem, you see the error message Windows Installer Error 4099, which indicates that because the Windows Installer is not properly registered on your computer, the installation of Dotnetfx.exe cannot proceed.
You must register the Windows Installer again:
1- Go to Start > Run, type cmd, and click OK.
2- At the command prompt, type msiexec.exe /unregister and click Enter.
3- Type msiexec.exe /regserver and click Enter to register your Windows Installer properly.
4- Restart the Mirra installation.
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