java.lang.NullPointerException
       at
com.sun.org.apache.xerces.internal.parsers.AbstractDOMParser.startElement
(AbstractDOMParser.java:1029)
       at
com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanStartElement
(XMLDocumentFragmentScannerImpl.java:1359)
       at
com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl
$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2747)
       at
com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next
(XMLDocumentScannerImpl.java:648)
       at
com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument
(XMLDocumentFragmentScannerImpl.java:510)
       at
com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse
(XML11Configuration.java:807)
       at
com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse
(XML11Configuration.java:737)
       at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse
(XMLParser.java:107)
       at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse
(DOMParser.java:225)
       at
com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse
(DocumentBuilderImpl.java:283)
       at javax.xml.parsers.DocumentBuilder.parse
(DocumentBuilder.java:124)
       at twitter4j.http.Response.asDocument(Response.java:119)

- Concurrency Issue with Twitterati
http://groups.google.com/group/twitter4j/browse_thread/thread/71dc64ad40a55b2a