Errors i can't understand

[c#_novice]

I use forward declaration to include class interface but get errors. Class Contract uses Class Date...

My Date.cpp

#include <time.h>
#include <iosfwd>

class Date						
{
public:

	Date() {
		SetDate( getCurrentTime() );
	}

	void SetDate(tm curr_tm)
	{
		day = curr_tm.tm_mday;
		month = curr_tm.tm_mon;
		year = curr_tm.tm_year;
		hour = curr_tm.tm_hour;
		minute = curr_tm.tm_min;
		local_dt = curr_tm;
	}

	static tm getCurrentTime()
	{
		time_t rawtime;
		tm* timeinfo;

		time( &rawtime );
		timeinfo = localtime ( &rawtime );

		return *timeinfo;
	}

	int getDay(){return day;}
	int getMonth(){return month;}
	int getYear(){return year;}
	int getHour(){return hour;}
	int getMinute(){return minute;}
	tm getLocalDT(){return local_dt;}

private:

	int day;
	int month;
	int year;
	int hour;
	int minute;
	tm local_dt;
};

Contract.h

// Class CONTRACT: Handles the rental contract details

#include <string>
#include <iosfwd>
//#include <iomanip>
//#include <fstream>
//#include <iostream>
//#include "Date.h"

class Date;

class Contract
{
public:
	
	Contract();

	void SetContractDetails(Date i, unsigned carR, const std::string& kms, float ratePD,
		unsigned lndrID, const std::string& contID, int days);

	void SetContractPeriod(Date i_dt, Date r_dt, int d, bool isLtd);
	void SetReturnDate();
	void DisplayContract();
	void Read(std::istream&, Contract&, bool);
	void Write(std::ostream&, bool);
	const std::string& getContractID() const;
	int getContractPeriod() const;
	float getRatePerDay() const;
	const std::string& getKmType() const;
	Date getIssueDate() const;
	Date getReturnDate() const;
	unsigned getLenderID() const;
	unsigned getCarReg() const;

private:
	std::string contractID;
	Date issued, returned;
	unsigned lenderID;
	unsigned carRegistration;
	int contractDays;
	std::string kmType;
	float dailyRate;
};
std::istream& operator >> (std::istream& in, Contract& rental);

Errors....

: error C2079: 'Contract::issued' uses undefined class 'Date'
: error C2079: 'Contract::returned' uses undefined class 'Date'
: error C2228: left of '.getDay' must have class/struct/union
1>        type is 'int'
: error C2228: left of '.getMonth' must have class/struct/union
1>        type is 'int'
: error C2228: left of '.getYear' must have class/struct/union
1>        type is 'int'
: error C2228: left of '.getHour' must have class/struct/union
1>        type is 'int'

etc...