WordPress: Problem installing on dedicated windows server 2008/IIS7

I'm having trouble with installing WordPress on a dedicated Microsoft Windows Web Server 2008 R2.

I've installed WordPress Version 2.9.2 from Web platform installer 3.0.

After installation when I try to access wordpress, either from ~/index.php or ~/wp-admin/install.php I get the error:

HTTP Error 500.0 – Internal Server Error
File monitoring is enabled for a file which could not be found

Modul: FastCgiModule
Notification: ExecuteRequestHandler
Handler: PHP52_via_FastCGI
Error Code: 0x80070003

I have both .Net 2.0 and .Net 4.0 installed.

Adding a "phpinfo.php" gives me the same error.

The application pool in IIS7 that's used for the website is: "No Managed Code" and set to "Integrated" in "Managed Pipeline Mode".

I've tried to reboot the machine.

What's more can I try?