[Vince]

pawn Код:

if(sscanf(params,"s[64]",text)) SendClientMessage(playerid, cinza, "/x <texto>");

Is not necessary, as you have only one param to pass.
Remove the sscanf line, and replace your format function with this one:

pawn Код:

format(string, sizeof(string), "CHAT: %s [ID: %d]: %s", name, playerid, params);

Then it should work.