How do I resolve "%1 is not a valid Win32 application"?

Question

Environment:
Windows Server 2003 R2 Enterprise 64bit, SP2
.NET framework is supposedly installed (2.0 SP2, 3.0 SP2, 3.5 SP1)

I say "supposedly" because they are listed as installed under Add/Remove programs. I'm not sure it's properly installed, because the "ASP.NET" tab isn't added to any of the sites in IIS.

In the IIS Web Service Extensions section, I have both "ASP.NET v2.0.50727" (Allowed), and "ASP.NET v2.0.50727 (32-bit)" (Prohibited).

The site in question has script-execute enabled.

Problem:

I created a super-simple ASP.NET/C# website: Default.aspx with a label id="Label1", and a code-behind with: Label1.text = "Hello World"; and the error I'm getting is:

%1 is not a valid Win32 application.

Answer 1

Also check your application pool. In a 64-bit environment, you may need to set "Enable 32-bit applications" in Advanced Settings.