Errors when running ASP Classic alongside ASP.NET in IIS 7.5

Question

I am currently trying to migrate some websites from IIS6 to IIS7 and have run into a problem.

For the most part, my websites are written in Classic ASP. However, within one website I have two web applications running asp.net. Something like this

www.mywebsite1.com - Classic ASP
www.mywebsite2.com - Classic ASP
www.mywebsite2.com/MyAspDotNetApplication1 - ASP.NET 4.0
www.mywebsite2.com/SubDirectory/MyAspDotNetApplication2 - ASP.NET 4.0
www.mywebsite3.com - Classic ASP
...

When I browse the sites hosting Classic ASP pages I have no problems. If I access one of the ASP.NET web application everything is ok. If I then access the second ASP.NET web application things start going wrong I get errors on the ASP.NET application pages along the lines of

Failed to start monitoring changes to '\FileServer1\web\mywebsite2\MyAspDotNetApplication1\App_Browsers' because the network BIOS command limit has been reached. For more information on this error, please refer to Microsoft knowledge base article 810886. Hosting on a UNC share is not supported for the Windows XP Platform.`

When I try to access the Classic ASP web pages I get the following error

HTTP Error 500.19 - Internal Server Error
The requested page cannot be accessed because the related configuration data for the page is invalid
Module  IIS Web Core
Notification    BeginRequest
Handler Not yet determined
Config Error    
Config File
Requested URL   http://www.mywebsite2.com:80/myvirtualdirectory1/
Physical Path   \\FileServer1\web\mywebsite2\myvirtualdirectory1\
Logon Method    Not yet determined
Logon User  Not yet determined

When I open up IIS manager and take a look at one of the sites or virtual directories where the error is occurring I get the following error

Filename: \\?\FileServer1\mywebsite2\web.config
Error: Cannot read configuration file

The problems I am having is similar to this other question but I have removed all Web.config files from all my sites (excluding the ASP.NET applications) and I still get the error.

This worked fine on IIS6.

Any ideas?

Setup

Hardware

• Two web servers (Web1 and Web2) running Windows Server 2008
• One file server (FileServer1) running Windows 2003 (don't know if that makes a difference)

IIS

• 10 Classic ASP websites running in their own application pools. These websites all have lots of virtual directories pointing to locations on the file server
• 20 websites that simply redirect to one of the 10 websites above
• 2 ASP.NET applications that sit inside of one of the Classic ASP sites
• The Classic ASP sites each have their own Application Pool which runs under a custom user account MYDOMAIN\MyIISUser
• The ASP.NET applications also have their own Application Pools and are configured to run under the custom user account MYDOMAIN\MyIISUser
• The 20 redirection websites run under a single Application Pool.
• The websites are set up to use shared configuration. The configuration files are stored locally on each web server and are synchronized using DFS (I tried putting it on the FileServer1 but ran into the same problem as above, moving it to the web servers local file system solved the issue - This may be important?).

File Server

• All web content is stored on the file server under C:\Web. This is set up as a UNC drive accessible from the network via the address \\FileServer1\Web
• I have set the permissions on C:\Web to allow Read access for the MYDOMAIN\MyIISUser
• I have been told that the web content must be stored on the network drive rather than have local copies and using DFS

Answer 1

It turns out that there is something wrong with the the fileserver. What the problem is I don't know. After creating a new clustered Windows Server 2008 fileserver I have not been able to replicate the problem.

Answer 2

It sounds like your ISAPI modules are not configured correctly on your classic ASP sites.

All .NET ISAPI filters should be disabled/disallowed and the classic ASP filter should be enabled.