looks like Demonbuddy itself currently does not extract the party members' area anymore. So we can't fix it for now :/
Not much of Trinity was using that data and they found a way to get it from somewhere else. and some debugging tool in Adventurer used it but that code simply got commented out.
I found that PlayerData seems to have replaced CPlayer. It is available through the PlayerDataManager, which even returns the correct number of party members - but their LevelAreaSnoId is always -1.
which is probably why none of the follow routines work. Maybe PM this to one of the staff here see if they can fix it.