[RoboN1X]

use capital "I" specifier for second parameter, this makes the parameter optional to enter, then first you check if player is online, then check if level is entered. Here i make it optional so it can be handled by your code instead of resulting "USAGE: /makeadmin [player-id] [admin-level]".

Код:

COMMAND:makeadmin(playerid, params[])
{
	if(PlayerInfo[playerid][pAdmin] >= 5)
	{
		new newadmin, adminlevel;
		if(sscanf(params, "uI", newadmin, adminlevel)) return SendClientMessage(playerid, -1, "USAGE: /makeadmin [player-id] [admin-level]")
		if(newadmin == INVALID_PLAYER_ID)
		{
			return SendClientMessage(playerid, 0xFFFFFFFF, "ERROR: That player is offline!");
		}
		else // player is connected
		{
			if(1 <= adminlevel <= 5) // check if entere admin level is 1 to 5
			{
				new newadminname[MAX_PLAYER_NAME], prom[128];
				GetPlayerName(newadmin, newadminname, MAX_PLAYER_NAME);
				format(prom, sizeof(prom), "You have promoted %s to a level %d administrator/moderator", newadminname, adminlevel);
				SendClientMessage(playerid, 0xFFFFFFFF, prom);
				format(prom, sizeof(prom), "You have been promoted by Admin %s to a level %d administrator/moderator", RemoveUnderScore(playerid), adminlevel);
				SendClientMessage(newadmin, 0xFFFFFFFF, prom);
				PlayerInfo[newadmin][pAdmin] = adminlevel;
				return 1;
			}
			else // level was not entered or not 1 to 5
			{
				SendClientMessage(playerid, 0xFFFFFFFF, "USAGE: Available Adminstration levels are:");
				SendClientMessage(playerid, 0xFFFFFFFF, "USAGE: Level 1: Moderator");
				SendClientMessage(playerid, 0xFFFFFFFF, "USAGE: Level 2: Junior Admin");
				SendClientMessage(playerid, 0xFFFFFFFF, "USAGE: Level 3: General Admin");
				SendClientMessage(playerid, 0xFFFFFFFF, "USAGE: Level 4: Community Manager");
				SendClientMessage(playerid, 0xFFFFFFFF, "USAGE: Level 5: Executive Admin");
				return 1;
			}
		}
	}
}

Not tested yet, hope that helps.