Persisten (HTTP Error 401.3 - Unauthorized: Access is denied due to an ACL)

Hi there,

I've installed a x64 2003 R2 server and want to host some asp.net
webapps, but am constantly running into the error

HTTP Error 401.3 - Unauthorized: Access is denied due to an ACL set on
the requested resource.

I've enabled 32 bit asp.net for my 32 bits apps and set the acls on my
webfolders, but the issue persist. The sites are using anonymous
access and at this point I've allowed full rights to the iusr account
and the app_pool accounts, just to be sure. No explicit deny rights
have been set.

When I run a filemon session I do not see any access denied messages.
I see the following:

w3wp.exe queries security on the C:\WINDOWS\Microsoft.NET\Framework
\v2.0.50727\aspnet_isapi.dll and then returns the default IIS 401.3
page.

This error is driving me nuts.

Any ideas?

Regards,

Mark