I spent a day trying to make Ent Lib Logging work and log anything into database or event log. I have a web application and console application with the same Ent Lib config but
I believe that under IIS7 (which I am assuming you are using) the application pool will be running under NETWORK SERVICE.
You could try giving NETWORK SERVICE Full Control to the registry key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Eventlog\Application
.
(Not Recommended!)
Alternatively, you could grant EVERYONE Full control to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Eventlog\Application
, log a message, then revert that change. Once the key is set up then you won't need the permissions to write to the registry.
Or you could manually configure the registry keys that you require beforehand to avoid the permission problems:
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Eventlog\Application\Logger]
"EventMessageFile"="c:\\WINNT\\Microsoft.NET\\Framework\\v2.0.50727\\EventLogMessages.dll"
Just an update to this answer that according to MSDN: "To create an event source in Windows Vista and later or Windows Server 2003, you must have administrative privileges".