I solved this on a Win2000 server by changing the Application Pool of the failing web app to a Framework 2.0 pool (from Default which must have had a Framework 1.1 app assigned to it).
This behavior can occur because the ASPNET account does not have sufficient permissions for the parent directory or for the child directory of the ASP.NET 1.1 application. See ME919075
to fix the problem.
This problem can occur when ASP.NET 2.0 is running under a custom service account. The custom service account does not have access permissions to the Microsoft Internet Information Services (IIS) metabase and other directories that are used by ASP.NET. See ME911714
for information on how to solve this problem.
for additional information about this event.
From a newsgroup post: "Go to IIS -> Default Web Sites -> right-click my Virtual Web Site -> choose option "All Tasks/Check & Reset Server Extentions" -> On pop-up message to use Front Page to tighten up security respond by choosing "Yes". This fixed my problem".
From a newsgroup post: "With a command window, go to the place the most recent version of .Net is installed, typically C:\Windows\Microsoft.Net\Framework\. Now run "net stop w3svc" to stop web services. Then, run "aspnet_regiis.exe -ua" to uninstall all instances of ASP.NET from IIS. Finally, type "aspnet_regiis.exe -i" to install ASP.NET into IIS and restart web services with "net start w3svc". After this, I was able to reload my browser and properly view my page".
I have IIS 6.0 running on a Windows 2003 Server Standard Edition domain controller. I have created a virtual site named Intranet. After all the operations indicated by Mihai Andrei I needed to do the following:
1. Grant execute permissions for group "Authenticated Users" to %windir%\Microsoft.Net and all subfolders.
2. Grant execute permissions for group "Authenticated Users" to Intranet root directory and all subfolders.
I ran “aspnet_regiis.exe –I” from the framework version folder (typically C:\WINDOWS\Microsoft.NET\Framework\v1.1.4322). This registers that version of the framework with IIS. It solved my case on a W2K system.
This is a NTFS permission issue. ASP.NET Web applications usually run using the built-in ASPNET account, but occasionally default access permissions are lost. Verify minimum needed permission for ASPNET account to run applications. Refer to section 2 and 3 of Building Secure ASP.NET Applications document.
ASP.NET Does Not Work with the Default ASPNET Account on a Domain Controller. See ME315158
All this really means is that your web directory permissions were wrong. In our case we were recieving this error in the event log whenever a particular site try to access any .Net resource. It turned out the permissions were wrong - i.e. Everyone user needed more access and/or IUSR_COMPUTERNAME needed more access such as READ.
In my case, Server Small Business 2K, SP4, if I reboot the server, the problem goes away.
From a newsgroup post: "I've managed to determine that the error will go away if I switch IIS6 to its default process isolation scheme (it had been set to IIS5 compatibility.) However, it seems I ran into a slightly worse situation: the problem still existed ("Server Application Unavailable" when trying to access any .aspx page), but I was not getting any errors in the event log now. Finally I reinstalled Win2k3 and the problem was fixed".
If you receive the error: "Server Application Unavailable" when trying to access any .aspx page, see ME315158
to find out how you can fix this problem.