Solidity错误:JSON中的意外标记h位于

嘿,我正在开发一个简单的关于solidity的智能合约,我遇到了一个问题。每次尝试运行setWord函数时,我都会收到一个错误“transact to HelloWorldContract.setWord errored:error encoding arguments:SyntaxError:JSON中位置2的意外标记h”可能是什么问题?

pragma solidity ^0.4.0;
contract HelloWorldContract{
string word = "Hello World";
address issuer;
function HelloWorldContract(){
    issuer = msg.sender;    
}
function getWord() constant returns(string) {
    return word;
}
function setWord(string newWord) returns(string) {
    if(issuer != msg.sender){
        return "this is not the creator!";
    }
    else{
     word = newWord;
     return "this is the creator!";
    }
}
}