Android SDK升级到4.1出现的错误：Please ensure that adb is correctly located at...

SDK升级到4.1后运行程序出现如下错误：

[2012-07-04 13:06:43 - A_GraphicsTest] The connection to adb is down, and a severe error has occured.
[2012-07-04 13:06:43 - A_GraphicsTest] You must restart adb and Eclipse.
[2012-07-04 13:06:43 - A_GraphicsTest] Please ensure that adb is correctly located at 'D:\AndroidSDK\android-sdk_r06-windows\android-sdk-windows\platform-tools\adb.exe' and can be executed.

重启eclipse或者重启电脑都是无济于事的，解决方法是：

修改环境变量path，原来只包含了：D:\AndroidSDK\android-sdk_r06-windows\android-sdk-windows\tools;

再将D:\AndroidSDK\android-sdk_r06-windows\android-sdk-windows\platform-tools;也加入到path中就OK了。

PS：SDK升级后ADT需要升级到最新版ADT20，但是eclipse-SDK-3.6总是无法成功升级ADT（出现各种各种问题），所以就下载了eclipse最新版juno，安装ADT20非常顺利。