Nina,
I read the post, and downloaded and watched the video, and I'm still missing it! I hadn't read anywhere else that I needed to use host headers, but maybe I do. Here is the layout, in brief.
I have a base dnn install, that I can get to right now, at http://ipaddress/dotnetnuke
I created a parent portal and told it to use directory \portals\seespto
I have a domain name seespto.org, that is pointed to ipaddress in it's dns configuration
At this point, I have host headers configured in iis as follows:
ip address port host headers
Default 80 "blank"
Default 80 "seespto.org"
Default 80 www.seespto.org
From the DNN server, I cannot browse to http://localhost/seespto, nor can I get to it any other way remotely. The directory was created.
I'm sure what's wrong here is a simple step, but I'm not seeing it!