The Windows NT 4.0 Option Pack (NTOP) documentation is dependent upon ASP (Active Server Pages) for IIS 4.0 (Internet Information Server). Chances are ASP for IIS 3.0 is installed.
To fix the problem:
1. Run the ASP Uninstall program.
2. Uninstall IIS 4.0 by running the NTOP Setup.
3. Shutdown and restart your Windows NT computer.
4. Install IIS 4.0.