The way I think I understand it (and I might be wrong) is that if you are using a dll that allows up to 34 players then you must accommodate that possibility in your World Builder maps.
Take any map that was created in World Builder (vanilla, Warlords, or BtS). Using your favorite text editor, change the beginning of it to look like this:
Code:
Version=11
BeginGame
Calendar=CALENDAR_DEFAULT
GameTurn=0
StartYear=-4000
EndGame
BeginPlayer
Team=0
LeaderType=NONE
CivType=NONE
RandomStartLocation=true
EndPlayer
BeginPlayer
Team=1
LeaderType=NONE
CivType=NONE
RandomStartLocation=true
EndPlayer
BeginPlayer
Team=2
LeaderType=NONE
CivType=NONE
RandomStartLocation=true
EndPlayer
BeginPlayer
Team=3
LeaderType=NONE
CivType=NONE
RandomStartLocation=true
EndPlayer
BeginPlayer
Team=4
LeaderType=NONE
CivType=NONE
RandomStartLocation=true
EndPlayer
BeginPlayer
Team=5
LeaderType=NONE
CivType=NONE
RandomStartLocation=true
EndPlayer
BeginPlayer
Team=6
LeaderType=NONE
CivType=NONE
RandomStartLocation=true
EndPlayer
BeginPlayer
Team=7
LeaderType=NONE
CivType=NONE
RandomStartLocation=true
EndPlayer
BeginPlayer
Team=8
LeaderType=NONE
CivType=NONE
RandomStartLocation=true
EndPlayer
BeginPlayer
Team=9
LeaderType=NONE
CivType=NONE
RandomStartLocation=true
EndPlayer
BeginPlayer
Team=10
LeaderType=NONE
CivType=NONE
RandomStartLocation=true
EndPlayer
BeginPlayer
Team=11
LeaderType=NONE
CivType=NONE
RandomStartLocation=true
EndPlayer
BeginPlayer
Team=12
LeaderType=NONE
CivType=NONE
RandomStartLocation=true
EndPlayer
BeginPlayer
Team=13
LeaderType=NONE
CivType=NONE
RandomStartLocation=true
EndPlayer
BeginPlayer
Team=14
LeaderType=NONE
CivType=NONE
RandomStartLocation=true
EndPlayer
BeginPlayer
Team=15
LeaderType=NONE
CivType=NONE
RandomStartLocation=true
EndPlayer
BeginPlayer
Team=16
LeaderType=NONE
CivType=NONE
RandomStartLocation=true
EndPlayer
BeginPlayer
Team=17
LeaderType=NONE
CivType=NONE
RandomStartLocation=true
EndPlayer
BeginPlayer
Team=18
LeaderType=NONE
CivType=NONE
RandomStartLocation=true
EndPlayer
BeginPlayer
Team=19
LeaderType=NONE
CivType=NONE
RandomStartLocation=true
EndPlayer
BeginPlayer
Team=20
LeaderType=NONE
CivType=NONE
RandomStartLocation=true
EndPlayer
BeginPlayer
Team=21
LeaderType=NONE
CivType=NONE
RandomStartLocation=true
EndPlayer
BeginPlayer
Team=22
LeaderType=NONE
CivType=NONE
RandomStartLocation=true
EndPlayer
BeginPlayer
Team=23
LeaderType=NONE
CivType=NONE
RandomStartLocation=true
EndPlayer
BeginPlayer
Team=24
LeaderType=NONE
CivType=NONE
RandomStartLocation=true
EndPlayer
BeginPlayer
Team=25
LeaderType=NONE
CivType=NONE
RandomStartLocation=true
EndPlayer
BeginPlayer
Team=26
LeaderType=NONE
CivType=NONE
RandomStartLocation=true
EndPlayer
BeginPlayer
Team=27
LeaderType=NONE
CivType=NONE
RandomStartLocation=true
EndPlayer
BeginPlayer
Team=28
LeaderType=NONE
CivType=NONE
RandomStartLocation=true
EndPlayer
BeginPlayer
Team=29
LeaderType=NONE
CivType=NONE
RandomStartLocation=true
EndPlayer
BeginPlayer
Team=30
LeaderType=NONE
CivType=NONE
RandomStartLocation=true
EndPlayer
BeginPlayer
Team=31
LeaderType=NONE
CivType=NONE
RandomStartLocation=true
EndPlayer
BeginPlayer
Team=32
LeaderType=NONE
CivType=NONE
RandomStartLocation=true
EndPlayer
BeginPlayer
Team=33
LeaderType=NONE
CivType=NONE
RandomStartLocation=true
EndPlayer
The text I've given above should replace all the text in the World Builder file that appears before the word "BeginMap".
Notice that the team number starts with 0 and ends with 33? That's done in order to allow for 34 civilizations on your map.
HOWEVER... DON'T FORGET TO DELETE ALL UNITS, CITIES AND TEAMREVEALS!
If your World Builder map contains placed units and cities, those will need to be deleted from the text of the World Builder file. If units and/or cities were present on the map, you'll have to delete all indications that any part of the map has been revealed to any team. Search for all lines containing the word "unit, "city," and "teamreveal."
Someone ought to write a simple program that automatically "cleans" World Builder text file maps of units, cities, and teamreveals. I'm very surprised that no one has done this already. Doing it by hand using a text editor is tedious and takes a long time. But it can be done!
The result of all this work is a map that has no civilizations. You can choose whatever civs you want in the game menu and they will be randomly placed on the map.
If you are working with an Earth map, you can pick your civs, let them be randomly placed on the map, and then manually place the units in World Builder. However, there is still the problem of randomly placed teamreveals throughout the map. The best solution is to plan ahead. Make a vanilla version of your Earth map and then use MapView to determine the starting locations of the civlizations.
Unfortunately, I don't have time this morning to fully explain how I work on Earth maps but hopefully what I've just posted will help.
EDIT: I can't get this to work with more than 30 pre-placed civs on a map.