Flex 上传问题！！！！！！急！！！！！

java.lang.NoSuchMethodError: org.apache.commons.fileupload.FileUpload.<init>(Lorg/apache/commons/fileupload/FileItemFactory;)V
at org.apache.commons.fileupload.servlet.ServletFileUpload.<init>(ServletFileUpload.java:95)
at com.ebook.actions.FileUploadServlet.processRequest(FileUploadServlet.java:59)
at com.ebook.actions.FileUploadServlet.doPost(FileUploadServlet.java:105)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:286)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Thread.java:619)网上说是包的问题，可是我不知道应该用哪个包。我用的是commons-fileupload-1.1.1.jar，哪们大侠告诉下，急！！！！！！！！！