Multisite Install - New blog creation redirection error

Have network install using subfolders:
http://www.mysite.com/

Adding new site. Site adds fine and shows as a site under the Network Admin. New site messages are delivered; etc.

Only; When I try to visit the site and/or the site's dashboard, I get this error message:
"The page isn't redirecting properly
Firefox has detected that the server is redirecting the request for this address in a way that will never complete.
This problem can sometimes be caused by disabling or refusing to acceptcookies."

I can access a dashboard and the site ONLY through the main site. All clicks on anything on the sub-site get the error.

I have other network installs that I access from the same computer; same browser; same session; that behave properly.

What would cause one site to create this message and another not to?

I have disabled all plugins; moved to twenty eleven and/weaver II themes only; permalinks set to /%postname% on the accessible main site within the network.