调用OSSClient方法都返回：ClientExceptionTheserverreturnsanunknownerror.

我拿了 OSSObjectSample.java 在 netbeans 里调试， 任何方法调用都返回Connection error due to: The server returns an unknown error.
这是什么情况。  自带的程序为什么调不通？

Exception in thread "main" com.aliyun.openservices.ClientException: Connection error due to: The server returns an unknown error.
at com.aliyun.common.comm.ServiceClient.sendRequestImpl(ServiceClient.java:194)
at com.aliyun.common.comm.ServiceClient.sendRequest(ServiceClient.java:136)
at com.aliyun.openservices.oss.internal.OSSOperation.send(OSSOperation.java:59)
at com.aliyun.openservices.oss.internal.OSSBucketOperation.listBuckets(OSSBucketOperation.java:102)
at com.aliyun.openservices.oss.internal.OSSBucketOperation.bucketExists(OSSBucketOperation.java:189)
at com.aliyun.openservices.oss.OSSClient.doesBucketExist(OSSClient.java:227)
at com.aliyun.openservices.oss.OSSClient.isBucketExist(OSSClient.java:240)
at com.weilaidata.common.OSSObjectSample.ensureBucket(OSSObjectSample.java:76)
at com.weilaidata.common.OSSObjectSample.main(OSSObjectSample.java:57)
Caused by: com.aliyun.openservices.ClientException: The server returns an unknown error.
at com.aliyun.openservices.oss.internal.OSSExceptionFactory.createInvalidResponseException(OSSExceptionFactory.java:27)
at com.aliyun.openservices.oss.internal.OSSErrorResponseHandler.handle(OSSErrorResponseHandler.java:41)
at com.aliyun.common.comm.ServiceClient.handleResponse(ServiceClient.java:275)
at com.aliyun.common.comm.ServiceClient.sendRequestImpl(ServiceClient.java:173)
... 8 more
Caused by: com.aliyun.common.parser.ResultParseException: Failed to parse the response result.
at com.aliyun.common.parser.JAXBResultParser.getObject(JAXBResultParser.java:72)
at com.aliyun.openservices.oss.internal.OSSErrorResponseHandler.handle(OSSErrorResponseHandler.java:38)
... 10 more
Caused by: javax.xml.bind.UnmarshalException: unexpected element (uri:"", local:"title"). Expected elements are <{}Error>
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallingContext.handleEvent(UnmarshallingContext.java:647)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.Loader.reportError(Loader.java:243)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.Loader.reportError(Loader.java:238)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.Loader.reportUnexpectedChildElement(Loader.java:105)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallingContext$DefaultRootLoader.childElement(UnmarshallingContext.java:1048)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallingContext._startElement(UnmarshallingContext.java:483)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallingContext.startElement(UnmarshallingContext.java:465)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.SAXConnector.startElement(SAXConnector.java:135)
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.startElement(AbstractSAXParser.java:506)
at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.scanStartElement(XMLNSDocumentScannerImpl.java:376)
at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl$NSContentDriver.scanRootElementHook(XMLNSDocumentScannerImpl.java:602)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:3063)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$PrologDriver.next(XMLDocumentScannerImpl.java:881)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:607)
at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(XMLNSDocumentScannerImpl.java:116)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:488)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:835)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:764)
at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:123)
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1210)
at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:568)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal0(UnmarshallerImpl.java:202)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal(UnmarshallerImpl.java:174)
at javax.xml.bind.helpers.AbstractUnmarshallerImpl.unmarshal(AbstractUnmarshallerImpl.java:140)
at javax.xml.bind.helpers.AbstractUnmarshallerImpl.unmarshal(AbstractUnmarshallerImpl.java:123)
at com.aliyun.common.parser.JAXBResultParser.getObject(JAXBResultParser.java:70)