求助：testNG+selenium+jenkins 构建时报 找不到或无法加载主类 org.testng.TestNG

Jophy10

控制台的输出如下：
Started by user xiaozhou
Building in workspace C:\Users\zhou\.jenkins\workspace\web
Updating http://svn.hongshiwl.com/svn/docs/xiaozhou_test/webtestng at revision '2016-08-05T13:46:03.393 +0800'
At revision 974

No changes for http://svn.hongshiwl.com/svn/docs/xiaozhou_test/webtestng since the previous build
[web] $ cmd /c call C:\Users\zhou\AppData\Local\Temp\hudson8510195084761616408.bat

C:\Users\zhou\.jenkins\workspace\web>Set CLASSPATH=libs\testng.jar;libs\autoTests.jar

C:\Users\zhou\.jenkins\workspace\web>java org.testng.TestNG libs\testng.xml
错误: 找不到或无法加载主类 org.testng.TestNG

C:\Users\zhou\.jenkins\workspace\web>exit 1
Build step 'Execute Windows batch command' marked build as failure
Finished: FAILURE