IHS安装失败，请问下原因

环境如下：
OS Name: Linux  是企业版的redhat 6.0
OS Architecture: amd64
OS Version: 2.6.32-71.el6.x86_64
Current User ID: root
Current User Home: /root
Current Working Directory: /soft/IHS
IBM HTTP Server 7.0
使用root用户安装IHS的时候，我勾选了安装plugin，出现了如下故障：
这是IHS的日志：
(Nov 26, 2012 5:19:13 PM), Process, com.ibm.ws.install.ihs.ismp.actions.ExecWizardActionFromDirectory, err, java.io.IOException: Cannot run program "/opt/IBM/HTTPServe
r/bin/htpasswd" (in directory "/opt/IBM/HTTPServer"): java.io.IOException: error=2, No such file or directory
STACK_TRACE: 14
java.io.IOException: Cannot run program "/opt/IBM/HTTPServer/bin/htpasswd" (in directory "/opt/IBM/HTTPServer"): java.io.IOException: error=2, No such file or director
y
at java.lang.ProcessBuilder.start(ProcessBuilder.java:470)
at java.lang.Runtime.exec(Runtime.java:604)
at com.ibm.ws.install.ihs.ismp.actions.ExecWizardActionFromDirectory.executeProcess(ExecWizardActionFromDirectory.java:202)
at com.ibm.ws.install.ihs.ismp.actions.ExecWizardActionFromDirectory.execute(ExecWizardActionFromDirectory.java:307)
at com.installshield.wizard.StandardWizardListener.execute(StandardWizardListener.java:123)
at com.installshield.wizard.StandardWizardListener.currentBeanChanged(StandardWizardListener.java:106)
at com.installshield.wizard.Wizard$RunThread.run(Wizard.java:1569)
Caused by: java.io.IOException: java.io.IOException: error=2, No such file or directory
at java.lang.UNIXProcess.(UNIXProcess.java:197)
at java.lang.ProcessImpl.start(ProcessImpl.java:101)
at java.lang.ProcessBuilder.start(ProcessBuilder.java:463)
... 6 more
这是plugin的日志：
(Nov 26, 2012 5:19:12 PM), Process, com.ibm.ws.install.ni.ismp.actions.PopulateTitleBarAction, msg1, Web server plug-ins for WebSphere Application Server 7.0
(Nov 26, 2012 5:19:12 PM), Process, com.ibm.ws.install.plg.ismp.actions.PlgSilentInstallInputValidationAction, err, The input value /opt/IBM/HTTPServer/conf/httpd.conf
for the input option webServerConfigFile1 is not valid, please refer to sample response files for correct option values.
(Nov 26, 2012 5:19:12 PM), Process, com.ibm.ws.install.plg.ismp.actions.PlgSilentInstallInputValidationAction, err, The input value /opt/IBM/HTTPServer/conf/httpd.conf
for the input option webServerConfigFile1 is not valid, please refer to sample response files for correct option values.
(Nov 26, 2012 5:19:12 PM), Process, com.ibm.ws.install.plg.ismp.actions.PlgSilentInstallInputValidationAction, err, java.lang.Exception: The input value /opt/IBM/HTTPS
erver/conf/httpd.conf for the input option webServerConfigFile1 is not valid, please refer to sample response files for correct option values.
at com.ibm.ws.install.plg.ismp.actions.PlgSilentInstallInputValidationAction.checkInstallTypeInputs(PlgSilentInstallInputValidationAction.java:264)
at com.ibm.ws.install.plg.ismp.actions.PlgSilentInstallInputValidationAction.execute(PlgSilentInstallInputValidationAction.java:73)
at com.installshield.wizard.StandardWizardListener.execute(StandardWizardListener.java:123)
at com.installshield.wizard.StandardWizardListener.currentBeanChanged(StandardWizardListener.java:106)
at com.installshield.wizard.Wizard$RunThread.run(Wizard.java:1569)

大神们 帮帮忙 看下什么情况啊