In my base when I try to set permissions for others I find that I can't because of some SEN Account setting? Can anyone explain what this is and how to change it? Thanks
Are you sure it was SEN? That's probably a bug or a typo in the code, SEN belongs to Sony. They probably meant Xbox live or something like that.
Well their account could have user created content issues preventing them to be join your user created zone. This happens on PSN so it is reasonable to say it might happen on XBL. You'd have to ask the players you are trying to add.