Error: Unresolved external

Jeg har oprettet en klasse der skulle simulere en ElevatrosSkakt...
og den kommer med følende fejl...
Error: Unresolved external 'Reality::PersonState::setFloorNo(int)' referenced from C:\CPP\ELEVATOR\MAINSIMULATION.OBJ

Klassen ser ud som følger...

#include <iostream>
#include <vector>
#include "ElevatorShaft.h"
#include "ElevatorShaft.cpp"
#include "ElevatorState.h"
#include "ElevatorState.cpp"
#include "Elevator.h"
#include "Elevator.cpp"
#include "Floor.h"
#include "Floor.cpp"
#include "Person.h"
#include "Person.cpp"
#include "PersonState.h"
#include "PersonState.cpp"
using namespace std;
using namespace Control;
using namespace Reality;

    //HeaderFile
#ifndef MAINSIMULATION_H;
#define MAINSIMULATION_H;
class MainSimulation    {
    public:
        explicit MainSimulation(vector<Person> persons);
        int StartSimulation();
        void InitializePerons(vector<Person> persons);
    private:
        ElevatorShaft elvShaft;
};
#endif;


MainSimulation::MainSimulation(vector<Person> persons)    {
    InitializePerons(persons);
    StartSimulation();
}

int MainSimulation::StartSimulation()    {
    while(1)    {
        if(!elvShaft.hashMorePersons())    {
            return 0;
        } else    {
            elvShaft.timeTick();
        }
    }
}

void MainSimulation::InitializePerons(vector<Person> persons)    {
    for(int i = 0; i < persons.size(); i++)    {
        elvShaft.insertPerson(persons[i]);
    }
}


int main()    {
    vector<Person> p;

    Person p1(PersonState(8), 8, 1);
    p.push_back(p1);
    Person p2(PersonState(0), 0, 2);
    p.push_back(p2);
    Person p3(PersonState(1), 1, 6);
    p.push_back(p3);
    Person p4(PersonState(1), 1, 4);
    p.push_back(p4);

    MainSimulation ms(p);
}