编译通过后无法运行的问题

Exception in thread "main" java.langNoclassDeffounderror:TestSender源程序如下:
package net.xdevelop.mobile.client.test;import net.xdevelop.mobile.client.*;
import net.xdevelop.mobile.SMS;public class TestSender {
    public TestSender() {
    }
    public static void main(String[] args) {
        try {
            // 创建SMS
            SMS sms = new SMS("1234567890123", "Hello World!");            // 发送短信
            boolean rs = SMSSender.send(sms);            // 检查发送结果
            if (!rs) {
                System.out.println("短信发送失败：" + sms.getError()); // 获取错误信息
            }
            else {
                System.out.println("success");
            }
        }
        catch (Exception e) {
            System.out.println(e.getMessage());
        }
    }
}