no-option for subdirectory domains

Trying to clone the main site (http://balancemadison.com) to a staging/test site (http://balancemadison.com/esp/). The site is there, however, it's telling me that no such site exists. I also tried creating a new site but it only seems to accept sub-domains. My multi-site has already been created using sub-folder. What can I do?