Php XML错误。编码点火器XML-RPC

我使用Codeigniter类

我有get功能

public function get($request)
{
    $params = $request->output_parameters();
    $userId = (int)$params[0]["UserId"];

    $users = $this->user_model->get($userId);

    if( count($users) > 0 )
    {
        $result = $users[0];
        $response = array($result, 'struct');
        return $this->xmlrpc->send_response($response);
    }
    else
    {
        return $this->xmlrpc->send_error_message('404', 'Not Found');
    }
}

用户ID

要使用XML代码调用函数：

    <?xml version="1.0" encoding="UTF-8"?>
<methodResponse>
<fault>
    <value>
        <struct>
            <member>
                <name>faultCode</name>
                <value><int>2</int></value>
            </member>
            <member>
                <name>faultString</name>
                <value><string>The XML data received was either invalid or not in the correct form for XML-RPC. Turn on debugging to examine the XML data further.</string></value>
            </member>
        </struct>
    </value>
</fault>
</methodResponse>

得到
用户ID
1.

结果是一个响应：

    <?xml version="1.0" encoding="UTF-8"?>
<methodResponse>
<fault>
    <value>
        <struct>
            <member>
                <name>faultCode</name>
                <value><int>2</int></value>
            </member>
            <member>
                <name>faultString</name>
                <value><string>The XML data received was either invalid or not in the correct form for XML-RPC. Turn on debugging to examine the XML data further.</string></value>
            </member>
        </struct>
    </value>
</fault>
</methodResponse>

故障码
2.
断层串
接收到的XML数据无效或XML-RPC格式不正确。启用调试以进一步检查XML数据。

我做错了什么