Thanks- I did end up figuring this out iby making the following changes to the  "function doOnload" section:

function doOnLoad(result, URL, userurl, redirurl, timeleft) {

      if (timeleft) {
        mytimeleft = timeleft;
      }
      if ((result == 1) && (self.name == \"chillispot_popup\")) {
        doTime();
      }
      if ((result == 1) && (self.name != \"chillispot_popup\")) {
        chillispot_popup = window.open(URL, 'chillispot_popup', 'toolbar=0,scrollbars=0,location=0,statusbar=0,menubar=0,resizable=0,width=500,height=300');
      }
      if ((result == 2) || result == 5) {
   getCookies();
        document.form1.UserName.focus()
      }
      if ((result == 2) && (self.name != \"chillispot_popup\")) {
        chillispot_popup = window.open('', 'chillispot_popup', 'toolbar=0,scrollbars=0,location=0,statusbar=0,menubar=0,resizable=0,width=400,height=200');
        chillispot_popup.close();
      }
      if ((result == 12) && (self.name == \"chillispot_popup\")) {
        doTime();
        if (redirurl) {
          window.opener.top.location.href = redirurl;
        }
        else if (userurl) {
          window.opener.top.location.href = userurl;
        }
        else if (opener.home) {
          window.opener.top.location.href.home();
        }
        else {
          window.opener.top.location.href = \"about:home\";
        }
        self.focus();
        blur = 0;
      }
      if ((result == 13) && (self.name == \"chillispot_popup\")) {
        self.focus();
        blur = 1;
      }
    }

As you can see I'm using "window.opener.top.location.href"

I think this is easy to fix- can someone tell me if I'm on the right path? Users complain that on login, their home page is "locked" in the iframe I'm using for the hotspotlogin.cgi script. I'm using SurferTim's multilingual script ( http://www.dd-wrt.com/phpBB2/viewtopic.php?t=16085&highlight=hotspotlogin ).

Looks like this is the section that I need to work with:

      if ((result == 12) && (self.name == \"chillispot_popup\")) {
        doTime();
        if (redirurl) {
          opener.location = redirurl;
        }
        else if (userurl) {
          opener.location = userurl;
        }
        else if (opener.home) {
          opener.home();
        }
        else {
          opener.location = \"about:home\";
        }
        self.focus();
        blur = 0;
      }

Is there any easy command to use that will force the redirect page to open in a new browser window?