初学Android运行遇到问题，高手请进
[2012-02-20 16:11:48 - HelloWrold] Failed to install HelloWrold.apk on device 'emulator-5554!
[2012-02-20 16:11:48 - HelloWrold] (null)
[2012-02-20 16:11:48 - HelloWrold] Failed to install HelloWrold.apk on device 'emulator-5554': EOF
[2012-02-20 16:11:48 - HelloWrold] com.android.ddmlib.InstallException: EOF
[2012-02-20 16:11:48 - HelloWrold] Launch canceled!


请教高手这个是什么原因啊，在此先万分感谢啦

[解决办法]
没遇到过。模拟器设置正确并启动后运行第一个Hello World时很顺利。。