Non-administrative users may receive the error message above when attempting to add or edit an individual relationship on an organization record. Granting the users permission to the Address Add Form 2 and Address Edit Form 3 will resolve this issue. However, this also gives users the ability to add and edit addresses on constituent records, which may not be desirable.
Download and install the latest patch, which contains all fixes from previous patches. If you are running an older version, download and install the latest version and then the patch.