winreg.setRootKey is not a function

The following code is giving the above error. This is Mozilla 1.1 on Win2K. The code is a clone of the
example at http://developer.netscape.com/docs/manuals/xpinstall/example9.html#998204

Help, please? Thanks.

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// figure out if/where tomcat is installed based on version
// returns the path or null

function getTomcatBaseline(version){

   // can't use a double backslash before subkey - windows already puts it in.
   var subkey;        // the name of the subkey you are poking around in
   var winreg = getWinRegistry();

   if (winreg != null) {
     // where in the registry to look
     winreg.setRootKey(winreg.HKEY_LOCAL_MACHINE);
     if (version == "4.0")
       subkey  = "SOFTWARE\\Apache\\Apache Tomcat 4.0";
     else
       subkey  = "SOFTWARE\\Apache Group\\Tomcat\\4.1";

     // see what we can find
     return winreg.getValueString(subkey, ""); // chris says this will work for default
   } else {
     alert("Only works on windows for starters... sorry.");
     return null;
   }
}