Как создать метод, вызывающий оставшиеся токены в Escrow-контракте

Я использую Mist в одиночной сети.

Произошла ошибка в процессе создания условного депонирования после создания токена ERC20:

Ошибка компиляции:

КОД токена ERC20:

pragma solidity ^0.4.16;

interface tokenRecipient { function receiveApproval(address _from, uint256 
_value, address _token, bytes _extraData) public; }

contract TokenERC20 {
// Public variables of the token
string public name;
string public symbol;
uint8 public decimals = 0;
// 18 decimals is the strongly suggested default, avoid changing it
uint256 public totalSupply;

// This creates an array with all balances
mapping (address => uint256) public balanceOf;
mapping (address => mapping (address => uint256)) public allowance;

// This generates a public event on the blockchain that will notify clients
event Transfer(address indexed from, address indexed to, uint256 value);

// This notifies clients about the amount burnt
event Burn(address indexed from, uint256 value);

/**
 * Constrctor function
 *
 * Initializes contract with initial supply tokens to the creator of the contract
 */
function TokenERC20(
    uint256 initialSupply,
    string tokenName,
    string tokenSymbol
) public {
    totalSupply = initialSupply * 10 ** uint256(decimals);  // Update total supply with the decimal amount
    balanceOf[msg.sender] = totalSupply;                // Give the creator all initial tokens
    name = tokenName;                                   // Set the name for display purposes
    symbol = tokenSymbol;                               // Set the symbol for display purposes
}

/**
 * Internal transfer, only can be called by this contract
 */
function _transfer(address _from, address _to, uint _value) internal {
    // Prevent transfer to 0x0 address. Use burn() instead
    require(_to != 0x0);
    // Check if the sender has enough
    require(balanceOf[_from] >= _value);
    // Check for overflows
    require(balanceOf[_to] + _value > balanceOf[_to]);
    // Save this for an assertion in the future
    uint previousBalances = balanceOf[_from] + balanceOf[_to];
    // Subtract from the sender
    balanceOf[_from] -= _value;
    // Add the same to the recipient
    balanceOf[_to] += _value;
    Transfer(_from, _to, _value);
    // Asserts are used to use static analysis to find bugs in your code. They should never fail
    assert(balanceOf[_from] + balanceOf[_to] == previousBalances);
}

/**
 * Transfer tokens
 *
 * Send `_value` tokens to `_to` from your account
 *
 * @param _to The address of the recipient
 * @param _value the amount to send
 */
function transfer(address _to, uint256 _value) public {
    _transfer(msg.sender, _to, _value);
}

/**
 * Transfer tokens from other address
 *
 * Send `_value` tokens to `_to` on behalf of `_from`
 *
 * @param _from The address of the sender
 * @param _to The address of the recipient
 * @param _value the amount to send
 */
function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) {
    require(_value <= allowance[_from][msg.sender]);     // Check allowance
    allowance[_from][msg.sender] -= _value;
    _transfer(_from, _to, _value);
    return true;
}

/**
 * Set allowance for other address
 *
 * Allows `_spender` to spend no more than `_value` tokens on your behalf
 *
 * @param _spender The address authorized to spend
 * @param _value the max amount they can spend
 */
function approve(address _spender, uint256 _value) public
    returns (bool success) {
    allowance[msg.sender][_spender] = _value;
    return true;
}

/**
 * Set allowance for other address and notify
 *
 * Allows `_spender` to spend no more than `_value` tokens on your behalf, and then ping the contract about it
 *
 * @param _spender The address authorized to spend
 * @param _value the max amount they can spend
 * @param _extraData some extra information to send to the approved contract
 */
function approveAndCall(address _spender, uint256 _value, bytes _extraData)
    public
    returns (bool success) {
    tokenRecipient spender = tokenRecipient(_spender);
    if (approve(_spender, _value)) {
        spender.receiveApproval(msg.sender, _value, this, _extraData);
        return true;
    }
}

/**
 * Destroy tokens
 *
 * Remove `_value` tokens from the system irreversibly
 *
 * @param _value the amount of money to burn
 */
function burn(uint256 _value) public returns (bool success) {
    require(balanceOf[msg.sender] >= _value);   // Check if the sender has enough
    balanceOf[msg.sender] -= _value;            // Subtract from the sender
    totalSupply -= _value;                      // Updates totalSupply
    Burn(msg.sender, _value);
    return true;
}

/**
 * Destroy tokens from other account
 *
 * Remove `_value` tokens from the system irreversibly on behalf of `_from`.
 *
 * @param _from the address of the sender
 * @param _value the amount of money to burn
 */
function burnFrom(address _from, uint256 _value) public returns (bool success) {
    require(balanceOf[_from] >= _value);                // Check if the targeted balance is enough
    require(_value <= allowance[_from][msg.sender]);    // Check allowance
    balanceOf[_from] -= _value;                         // Subtract from the targeted balance
    allowance[_from][msg.sender] -= _value;             // Subtract from the sender's allowance
    totalSupply -= _value;                              // Update totalSupply
    Burn(_from, _value);
    return true;
}
}

"ESCROW" CODE:

pragma solidity ^0.4.18;


contract Owned {

address public owner;   

event TransferOwnerShip(address oldaddr, address newaddr);


modifier onlyOwner {require(msg.sender == owner);_;}


function Owned() public {
    owner = msg.sender;
}

function transferOwnership(address newOwner) onlyOwner public {
    address oldaddr = owner;
    owner = newOwner;
    TransferOwnerShip(oldaddr, owner);
}
}

interface token {
    function transfer(address receiver, uint amount) public;
}


contract Escrow is Owned {

token public tokenReward; //토큰
uint256 public salesVolume; //판매량
uint256 public sellingPrice; //판매가격
uint256 public deadline;     //기한
bool public isOpened;     //에스크로 개시 플래그

mapping(address => uint256) public balanceOf;

//(3)이벤트열람
event EscrowStart(uint salesVolume, uint sellingPrice, uint deadline, address beneficiary);
event ConfirmedPayment(address addr, uint amount);

//(4)생성자
function Escrow(
    address addressOfTokenUsedAsReward,
    uint256 _salesVolume,
    uint256 priceInEther

) public {
    tokenReward = token(addressOfTokenUsedAsReward);
    salesVolume = _salesVolume;
    sellingPrice = priceInEther * 1 ether;
}

//(5)이름없는함수(Ether 수령)
function () public payable {
    //개시 전 또는 기한이 끝난 경우에는 예외 처리
    require(!isOpened || now >= deadline);

    //판매 가격 미만인 경우 예외 처리
    uint amount = msg.value;
    require(amount < sellingPrice);

    ////보내는 사람에게 토큰을 전달하고 에스크로 개시 플래그를 false로 설정
    tokenReward.transfer(msg.sender, salesVolume);
    isOpened = false;
    ConfirmedPayment(msg.sender, amount);

}

//(6)개시(토큰이 예정 수 이상이라면 개시)
function start(uint256 _durationInMinutes) public {
    require(tokenReward == address(0) || salesVolume == 0 || sellingPrice == 0 || deadline !=0);
    if(tokenReward.balanceOf(this) >= salesVolume){
        deadline = now + _durationInMinutes * 1 minutes;
        isOpened = true;
        EscrowStart(salesVolume, sellingPrice, deadline, owner);
    }

}
//(7)남은 시간 확인용 메서드(분 단위)
function getRemainingTime() public constant returns(uint min){
    if(now < deadline) {
        min = (deadline - now) / (1 minutes);
    }
}
//(8)종료
function close() public {
    //토큰을 소유자에게 전송
   tokenReward.transfer(owner, tokenReward.balanceOf(this));
   //계약을 파기(해당 계약이 보유하고 있는 Ether는 소유자에게 전송)
   selfdestruct(owner);
}

}

Пожалуйста, дайте мне знать, если вам нужно что-то отредактировать или добавить.