ant编译时UNEXPECTED TOP-LEVEL EXCEPTION异常
新人求教啊！最近搭建持续集成系统，使用的是hudson+SVN+ant的配搭，当进行项目的构建时，在执行ant脚本到dex标签时，出现如下错误：dex:
[echo] Converting compiled files and external libraries into bin/classes.dex...
[apply]
[apply] UNEXPECTED TOP-LEVEL EXCEPTION:
[apply] com.android.dex.util.ExceptionWithContext
[apply] at com.android.dex.util.ExceptionWithContext.withContext(ExceptionWithContext.java:45)
[apply] at com.android.dx.dex.cf.CfTranslator.processMethods(CfTranslator.java:377)
[apply] at com.android.dx.dex.cf.CfTranslator.translate0(CfTranslator.java:139)
[apply] at com.android.dx.dex.cf.CfTranslator.translate(CfTranslator.java:94)
[apply] at com.android.dx.command.dexer.Main.processClass(Main.java:682)
[apply] at com.android.dx.command.dexer.Main.processFileBytes(Main.java:634)
[apply] at com.android.dx.command.dexer.Main.access(Main.java:78)
[apply] at com.android.dx.command.dexer.Main.processFileBytes(Main.java:572)
[apply] at com.android.dx.cf.direct.ClassPathOpener.processOne(ClassPathOpener.java:170)
[apply] at com.android.dx.cf.direct.ClassPathOpener.processDirectory(ClassPathOpener.java:229)
[apply] at com.android.dx.cf.direct.ClassPathOpener.processOne(ClassPathOpener.java:158)
[apply] at com.android.dx.cf.direct.ClassPathOpener.process(ClassPathOpener.java:144)
[apply] at com.android.dx.command.dexer.Main.processOne(Main.java:596)
[apply] at com.android.dx.command.dexer.Main.processAllFiles(Main.java:498)
[apply] at com.android.dx.command.dexer.Main.runMonoDex(Main.java:264)
[apply] at com.android.dx.command.dexer.Main.run(Main.java:230)
[apply] at com.android.dx.command.dexer.Main.main(Main.java:199)
[apply] at com.android.dx.command.Main.main(Main.java:103)
[apply] Caused by: java.lang.NullPointerException
[apply] at com.android.dx.cf.code.ConcreteMethod.<init>(ConcreteMethod.java:87)
[apply] at com.android.dx.cf.code.ConcreteMethod.<init>(ConcreteMethod.java:75)
[apply] at com.android.dx.dex.cf.CfTranslator.processMethods(CfTranslator.java:277)
[apply] ... 16 more
[apply] ...while processing run ()V
[apply] ...while.class
我在两天前构建时成功了，隔了一个双休日回来以后就一直是这样的失败，期间我在hudson外面包了一个tomcat的壳子，没有做其他的修改。
由于学习安卓还不久，这个问题又困扰了我很久，求大神帮助，在线等。谢谢 --------------------编程问答-------------------- 自己顶一下 高手求助
补充：移动开发 , Android
