Normally MiniVend determines which catalog to call by determining the SCRIPT_NAME from the CGI call. This means that different (and maybe virtual) hosts cannot use the same SCRIPT_NAME to call different catalogs. Set FullUrl to Yes to differentiate based on the calling host. You must then set the server name in the Catalog directive accordingly, i.e. yourdomain.com/cgi-bin/simple. A yes/no directive, the default is No.
FullUrl Yes