Making an ally doesn't always work correctly

Hi there. I am having a problem with the game i am making. What i am attempting to accomplish by this trigger is that when a player enters a region (selecting either cop or robber) it places them as the ally to everyone else in that playergroup. The problem is, when a person selects the unit, it doesn't always set them as allies to the other people! It works sometimes and sometimes it doesn't. This get's to be a real problem in the game i am creating. My trigger is below, if anyone knows of a better and more effective way to do this i'll be forever greatful and would even be willing to give credit to in my map =P

Maybe this is why
A personenters robber then a person enters before the unit is spawned causing this problem so the trigger has to be disabled so no one can do it until that person is done

ack well unfortunately i still have the same problem =\ i added a turn off trigger at the beginning and a turn on at the end, however it still ahs the same problem as before

Your trigger seemes to be really messed up.
I've added comment next to the trigger functions:

Events
Unit - A unit enters Choice Robber <gen>

Conditions
AllowedRobbers Greater than 0 -(what does Allowedrobbers stand for?)-

Actions

Set AllowedRobbers = (AllowedRobbers - 1)

Player Group - Add (Owner of (Triggering unit)) to Robber
Player Group - Pick every player in Robber and do (Actions)

Loop - Actions

Set PlayerVariable = (Picked player)
-(I'm assuming playervariable is not a playergroup but just a playervariable)-
-(cause you can't assign multiple players to a playervariable I'm assuming 'robber' now only consist of 'owner of triggering unit')-

HINT: If u assign multiple players to a playervariable the computer randomly picks one of the players u assigned.

Player Group - Pick every player in Robber -(which is the owner is triggering unit)-
and do (Player - Make PlayerVariable -(which also is the owner is triggering unit)-
treat (Picked player) -(himself!)-
as an Ally with shared vision)

Player Group - Pick every player in Robber -(which is the owner is triggering unit)-
and do (Player - Make (Picked player) -(which is the owner is triggering unit)-
treat PlayerVariable -(which is the owner is triggering unit) -as an Ally with shared vision)

Unit - Remove (Triggering unit) from the game

Unit - Create 1 Robber for (Owner of (Triggering unit)) at (Random point in Robber Spawn <gen> ) facing Default building facing degrees

If (AllowedRobbers Equal to 0) then do (Game - Display to (All players) for 3.00 seconds the text: All the Robbers hav...) else do (Do nothing)

Trigger - Run Leaderboard <gen> (ignoring conditions

I see what my problem is in your post, however i have absolutely no idea how i would go about fixing this problem. I hate begging for help when i have not made any contribution myself, but this one thing has had me stumped for over 3 days =\

You might want to try this:

Robber Spawn
Events
Unit - A unit enters Choice Robber <gen>
Conditions
AllowedRobbers Greater than 0
Actions
Set AllowedRobbers = (AllowedRobbers - 1)

Player Group - Pick every player in Robber and do (Player - Make (Owner of (Triggering Unit)) treat (Picked player) as an Ally with shared vision)

Player Group - Pick every player in Robber and do (Player - Make (Picked player) treat (Owner of (Triggering Unit)) as an Ally with shared vision)

Player Group - Add (Owner of (Triggering unit)) to Robber

Unit - Remove (Triggering unit) from the game

Unit - Create 1 Robber for (Owner of (Triggering unit)) at (Random point in Robber Spawn <gen> ) facing Default building facing degrees

If (AllowedRobbers Equal to 0) then do (Game - Display to (All players) for 3.00 seconds the text: All the Robbers hav...) else do (Do nothing)

If you could send me your map I could try and fix your problem.
Cause the trigger you posted doesn't really show me what you want to accomplish. Triggers are my field so I think fixing it won't be a problem.