(nutch)ant为什么编译不了build.xml文件

index-store文件下的build.xml文件是我自己写的插件的一个配置信息。但是在ant编译的时候报错了：错误如下：
F:\yanguinan\workspaces\SoftertechCrawl\src\plugin\index-store>ant
Buildfile: F:\yanguinan\workspaces\SoftertechCrawl\src\plugin\index-store\build.
xmlcompile-core:BUILD FAILED
F:\yanguinan\workspaces\SoftertechCrawl\src\plugin\build-plugin.xml:117: The fol
lowing error occurred while executing this line:
java.io.FileNotFoundException: F:\yanguinan\workspaces\SoftertechCrawl\build.xml
 (系统找不到指定的文件。)
        at java.io.FileInputStream.open(Native Method)
        at java.io.FileInputStream.<init>(FileInputStream.java:106)
        at org.apache.tools.ant.helper.ProjectHelper2.parse(ProjectHelper2.java:
278)
        at org.apache.tools.ant.helper.ProjectHelper2.parse(ProjectHelper2.java:
178)
        at org.apache.tools.ant.ProjectHelper.configureProject(ProjectHelper.jav
a:82)
        at org.apache.tools.ant.taskdefs.Ant.execute(Ant.java:393)
        at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:291)
        at sun.reflect.GeneratedMethodAccessor4.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAcces
sorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.jav
a:106)
        at org.apache.tools.ant.Task.perform(Task.java:348)
        at org.apache.tools.ant.Target.execute(Target.java:392)
        at org.apache.tools.ant.Target.performTasks(Target.java:413)
        at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1399)
        at org.apache.tools.ant.Project.executeTarget(Project.java:1368)
        at org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExe
cutor.java:41)
        at org.apache.tools.ant.Project.executeTargets(Project.java:1251)
        at org.apache.tools.ant.Main.runBuild(Main.java:811)
        at org.apache.tools.ant.Main.startAnt(Main.java:217)
        at org.apache.tools.ant.launch.Launcher.run(Launcher.java:280)
        at org.apache.tools.ant.launch.Launcher.main(Launcher.java:109)Total time: 0 seconds
各位大侠···帮忙看看···谢谢了！