So, was trying to get DNSdiag.exe to work on my laptop after installing the Windows Server 2003 Resource Kit. After installing the kit, running the command shell, and then running dnsdiag.exe, I got an error saying:
"Unable to locate component" and referring to isatq.dll, which lives in the C:\WINDOWS\system32\inetsrv folder.
I chased my tail for a bit trying to register that .dll with regsvr32.exe and installing IIS on my laptop, neither of whcih worked.
Then I copied dnsdiag.exe into the C:\WINDOWS\system32\inetsrv, and now it works fine.