Web Farm Framework configuration

Hi,

I configured Web Farm Framework on my servers. My controller is also my primary web server.
I deactivated load balancing as I have a dedicated load balancer.

Now each time I try to modify the configuration I get the followinf error :
Filename: \\?C:\Windows\system32\inetserv\config\applicationHost.config
Error: Cannot write configuration file.

I tried to run IIS Manager in administration mode. I checked the rights on the file, I can edit it with Notepad.

Also weird: I tried to edit the configuration directly in the file, it doesn't seem to be taken into account, is it the right configuration file ?

Thanks !