[CoDeZ]

ehm you forgot something

pawn Code:

if(sscanf(params,"us[128]",id,message)) return SendClientMessage(playerid, -1, "Syntax: /pm <id> <message>");// this is for your extension aka params, u is for the id s is for the string 'message'

and also here

pawn Code:

if(sscanf(params,"s[128]",message)) return SendClientMessage(playerid, -1, "Syntax: /r <message>");// same as the pm command

You have to add the string length else you will get warning at your console