[Freedom.]

Add this stock. And replace SetPlayerPos to SetPlayerPos_Ex

Code:

stock SetPlayerPos_Ex(playerid, Float:x, Float:y, Float:z)
{
    new vID = GetPlayerVehicleID(playerid);
	if(!IsPlayerInAnyVehicle(playerid))
	{
		SetPlayerPos(playerid, x, y, z);
	}
	else
	{
		SetVehiclePos(vID, x, y, z);
	}
	return 1;
}