JAVA图形界面。运行时出错！大家帮看看呗

别人家的一套接口演示程序，拿来运行时报错，错误信息如下
ant -f D:\\ClientDemo -Djavac.includes=ClientDemo/ClientDemo.java -Drun.class=ClientDemo.ClientDemo run-single
init:
Deleting: D:\ClientDemo\build\built-jar.properties
deps-jar:
Updating property file: D:\ClientDemo\build\built-jar.properties
Compiling 1 source file to D:\ClientDemo\build\classes
注: D:\ClientDemo\src\ClientDemo\ClientDemo.java使用了未经检查或不安全的操作。
注: 有关详细信息, 请使用 -Xlint:unchecked 重新编译。
compile-single:
run-single:
D:\ClientDemo\nbproject\build-impl.xml:801: D:\lib is not a valid directory
at org.apache.tools.ant.taskdefs.Java.setupWorkingDir(Java.java:855)
at org.apache.tools.ant.taskdefs.Java.setupExecutable(Java.java:825)
at org.apache.tools.ant.taskdefs.Java.fork(Java.java:788)
at org.apache.tools.ant.taskdefs.Java.executeJava(Java.java:214)
at org.apache.tools.ant.taskdefs.Java.executeJava(Java.java:135)
at org.apache.tools.ant.taskdefs.Java.execute(Java.java:108)
at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:291)
at sun.reflect.GeneratedMethodAccessor475.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
at org.apache.tools.ant.Task.perform(Task.java:348)
at org.apache.tools.ant.taskdefs.Sequential.execute(Sequential.java:68)
at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:291)
at sun.reflect.GeneratedMethodAccessor475.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
at org.apache.tools.ant.Task.perform(Task.java:348)
at org.apache.tools.ant.taskdefs.MacroInstance.execute(MacroInstance.java:398)
at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:291)
at sun.reflect.GeneratedMethodAccessor475.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java: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(DefaultExecutor.java:41)
at org.apache.tools.ant.Project.executeTargets(Project.java:1251)
at org.apache.tools.ant.module.bridge.impl.BridgeImpl.run(BridgeImpl.java:283)
at org.apache.tools.ant.module.run.TargetExecutor.run(TargetExecutor.java:541)
at org.netbeans.core.execution.RunClassThread.run(RunClassThread.java:153)
Java Result: -1
成功构建 (总时间: 0 秒)