403 - Forbidden: Access is denied in IIS 7

Question

I give up, tried just about everything I know.

Here's my setup:

1. running Subtext 2.5 open source blog software

2. this software runs under the .NET 4.0 app pool and the project is definitely running on the .NET 4.0 framework

3. I've set the app pool identity to use Network Service
4. I ensured that network service and IUSR both have full rights to that entire tree of my file system...my www tree which holds this app and a ton of others
5. I'm running Anonymous Auth. Tried the others with no luck such as impersonation, etc.

This is a localhost website on my Win 7 64-bit OS.

I still get this error at runtime and I just cannot figure out what I am missing here.

Not sure how to get the details of exactly what's going on behind this 403 outside the simple permission statement.

UPDATE, found this in the event log:

Event code: 3008 
Event message: A configuration error has occurred. 
Event time: 4/3/2011 11:07:06 PM 
Event time (UTC): 4/4/2011 4:07:06 AM 
Event ID: 9acd7ff588b248828651dc2c489727b1 
Event sequence: 1 
Event occurrence: 1 
Event detail code: 0 

Application information: 
    Application domain: /LM/W3SVC/1/ROOT/TestBlog-1-129463636261417394 
    Trust level: Full 
    Application Virtual Path: /TestBlog
    Application Path: C:\www\Subtext25_SVN_Repo4183\src\Subtext.Web\ 
    Machine name: HOMEBASE

Process information: 
    Process ID: 7108 
    Process name: w3wp.exe 
    Account name: IIS APPPOOL\SubtextNet4 

Exception information: 
    Exception type: ConfigurationErrorsException 
    Exception message: Unrecognized attribute 'targetFramework'. Note that attribute names are case-sensitive. (C:\www\Subtext25_SVN_Repo4183\src\Subtext.Web\web.config line 270) 

Request information: 
    Request URL: http://localhost/TestBlog/ 
    Request path: /TestBlog/ 
    User host address: 127.0.0.1 
    User:  
    Is authenticated: False 
    Authentication Type:  
    Thread account name: IIS APPPOOL\SubtextNet4 

Thread information: 
    Thread ID: 5 
    Thread account name: IIS APPPOOL\SubtextNet4 
    Is impersonating: False 
    Stack trace:    at System.Web.HttpRuntime.HostingInit(HostingEnvironmentFlags hostingFlags)