If Teamwork Server uses Subversion for storing projects and LDAP Integration for authentication, Subversion must recognize (or authenticate) the same users and passwords used to authenticate against the LDAP server. The Administrator is the user specified in the LDAP Integration configuration.
When Teamwork is integrated with Subversion only, the client's authentication information is passed to the Subversion server. When Teamwork Server is integrated with Subversion and LDAP, client's authentication information is passed to both Subversion server(s) and LDAP server(s), but only successful authentication to the LDAP server(s) successfully logs the user into Teamwork Server.