Prefixes dont show...! Help! (PEX)

I have a problem, prefixes dont show in my chat... I dont know how to explain it, so here's my permissions.yml, config.yml files and my plugin list:
Permissions.yml (PEX)= http://pastebin.com/UEXZnDtQ
config.yml (ChatManager)= http://pastebin.com/ts9cZvas
Plugin list= (29): Orebfuscator, WorldEdit, VisitCounter, PorteCoulissante, PvPTime, SafeExplosions, Vault, PermissionsEx, Stargate, Multiverse-Core, iConomy, AuthMe, CoreProtect, MineMaze, PvPTitles, BKCommonLib, Lockette, ClearLag, DeathMSG, MobArena, Essentials, AntiPvPLogger, Jobs, ChatManager, ServerSigns, EssentialsSpawn, RecipeManager, Factions, AntiCheat

I tried it all! I turned on and off chatmanager, I changed prefixes... But I dont know waths the problem!
Help please!

 

Try moving to another Chat plugin. HeroChat works without any problems and shows prefixes as it should.

 

I downloaded HeroChat and I drop it in my plugins folder, and I started the server, I logged in, I said: Hello! and any prefixes where shown... D:

Ok, I thinks the problem is an incompatibility with another plugin, cause I created a new server and I only put HeroChat and PermissionsEx in the plugins folder, and it worked... But now: How can I know wich is the "bad" plugin?
Plugins: Orebfuscator, WorldEdit, VisitCounter, PorteCoulissante, PvPTime, SafeExplosions, Vault, PermissionsEx, Stargate, Multiverse-Core, iConomy, AuthMe, CoreProtect, MineMaze, PvPTitles, BKCommonLib, Lockette, ClearLag, DeathMSG, Herochat, MobArena, Essentials, AntiPvPLogger, Factions, Jobs, ServerSigns, EssentialsSpawn, RecipeManager

help?

EDIT by Moderator: merged posts, please use the edit button instead of double posting.