Error Readout:"This configuration section cannot be used at this path. This happens when the section is locked at a parent level. Locking is either by default...
Fix:Change the following values located in the applicationHost.config file located in Windows\system32\inetsrv\config.
<section name="handlers" overrideModeDefault="Deny" /> change this value from "Deny" to "Allow"
<section name="modules" allowDefinition="MachineToApplication" overrideModeDefault="Deny" /> change this value from "Deny" to "Allow"
Explination:This error came up when I was setting up cruise control on windows 7 with iis 7. Cruise control sets the platform for creating custom handlers for their applicaiton in the future. Digging a little deeper you can see they set their custom handles to ".aspx" which means they aren't changing anything, but they do give a good explanation in the web.config file comments.
" <!-- Yes, we are overriding .aspx - don't delete this! We are using .aspx since we know it is already bound to ASP.NET. In future we might use a
different extension so that people can add their own ASP.NET pages if they want to, but we should make sure in that case to change how
URLs are created -->"
The discussion for this error is here
http://forums.asp.net/t/1220987.aspx