You have tried Appendix A in the Administrator Guide and you still encounter the error.
The Network Service is not granted the correct permission to write to the IIS metabase
- From the Start menu, select the Run… option.
- From %windir%\Microsoft.NET\Framework\version\, run the following command:
aspnet_regiis -ga "NT AUTHORITY\NETWORK SERVICE"
The “–ga” option grants the specified user or group access to the IIS metabase and other directories that are used by ASP.NET. This option is only available with ASP.NET version 2.0 or later.