使用selenium做自动化检测时报异常

异常如下：

org.openqa.selenium.InvalidElementStateException: [Exception... "Component returned failure code: 0x80004005 (NS_ERROR_FAILURE) [nsINativeMouse.click]"  nsresult: "0x80004005 (NS_ERROR_FAILURE)"  location: "JS frame :: file:///C:/Users/jzheng/AppData/Local/Temp/anonymous2759928925516801350webdriver-profile/extensions/fxdriver@googlecode.com/components/command_processor.js :: <TOP_LEVEL> :: line 9659"  data: no]
Command duration or timeout: 114 milliseconds
Build info: version: '2.28.0', revision: '18309', time: '2012-12-11 20:21:18'
System info: os.name: 'Windows 7', os.arch: 'amd64', os.version: '6.1', java.version: '1.6.0_33'
Session ID: c458e208-7f45-42fe-b4d0-5f7f32e36ec3
Driver info: org.openqa.selenium.firefox.FirefoxDriver
Capabilities [{platform=XP, acceptSslCerts=true, javascriptEnabled=true, browserName=firefox, rotatable=false, locationContextEnabled=true, version=17.0.7, cssSelectorsEnabled=true, databaseEnabled=true, handlesAlerts=true, browserConnectionEnabled=true, nativeEvents=true, webStorageEnabled=true, applicationCacheEnabled=true, takesScreenshot=true}]

。。。。

原先用了click 来完成，报错了，后面发现selenium自带有选择下拉单的方法，没再报错