So since I updated to the latest build.
If someone invites me I type /accept or /deny but NOTHING happens.
No errors, no message, just nothing.
I think its since I added iLottery, need to make further tests...
This are the plugins I use:
Announcer, Minequery, ConsoleFilter, Deadbolt, Vault, FalseBookCore, Announcements, WorldEdit, iConomy, PermissionsEx, ProtectionStones, Votifier, Spout, CommandBook, MobDisguise, MultipleHomes, iLottery, mcMMO, Colors, SignColours, WebAuction, TimTheEnchanter, FalseBookBlock, HeroChat, Permissions, WorldGuard, SimpleClans, ChestShop, PreciousStones, Register

Ok problem fixed.
I used the mcMMO Dev build and apparently its not compatible with SimpleClans.