Invalid application path

Solution 1:

When I got this error it appeared to be due to a security setting. When I changed the "Connect As" property to an administrator then I no longer got the message.

Obviously this isn't a good solution for a production environment - one should probably grant the least privileges necessary for the user IIS is going to be using by default. I'll update this answer if I learn more.

Solution 2:

The error message might be a bug. I ignored it and everything worked for me.

See Here: http://forums.iis.net/t/1177952.aspx

and here http://forums.iis.net/p/1182820/2000936.aspx

Solution 3:

I eventually tracked this down to the Anonymous Authentication Credentials. I don't know what had changed, because this application used to work, but anyway, this is what I did: Click on the Application -> Authentication. Make sure Anonymous Authentication is enabled (it was, in my case), but also click on Edit... and change the anonymous user identity to "Application pool identity" not "Specific user". Making this change worked for me.

Regards.