description:
npe when preview a report using a library

build:
2.6.0.v20100401-0630

steps to reproduce:
1. new a library
2. new a report and use the library
3. preview

actual result:
npe thrown out

expect result:
no error

errorlog:
java.lang.nullpointerexception
   at org.eclipse.birt.report.engine.api.impl.rendertask.(rendertask.java:122)
   at org.eclipse.birt.report.engine.api.impl.rendertask.(rendertask.java:90)
   at org.eclipse.birt.report.engine.api.impl.reportenginehelper.createrendertask(reportenginehelper.java:501)
   at org.eclipse.birt.report.engine.api.impl.reportengine.createrendertask(reportengine.java:480)
   at org.eclipse.birt.report.service.reportengineservice.createrendertask(reportengineservice.java:1604)
   at org.eclipse.birt.report.service.reportengineservice.renderreport(reportengineservice.java:1506)
   at org.eclipse.birt.report.service.birtviewerreportservice.getpage(birtviewerreportservice.java:204)
   at org.eclipse.birt.report.service.actionhandler.abstractgetpageactionhandler.doexecution(abstractgetpageactionhandler.java:238)
   at org.eclipse.birt.report.service.actionhandler.abstractgetpageactionhandler.__execute(abstractgetpageactionhandler.java:105)
   at org.eclipse.birt.report.service.actionhandler.abstractbaseactionhandler.execute(abstractbaseactionhandler.java:90)
   at org.eclipse.birt.report.soapengine.processor.abstractbasedocumentprocessor.__executeaction(abstractbasedocumentprocessor.java:47)
   at org.eclipse.birt.report.soapengine.processor.abstractbasecomponentprocessor.executeaction(abstractbasecomponentprocessor.java:143)
   at org.eclipse.birt.report.soapengine.processor.birtdocumentprocessor.handlegetpage(birtdocumentprocessor.java:87)
   at sun.reflect.nativemethodaccessorimpl.invoke0(native method)
   at sun.reflect.nativemethodaccessorimpl.invoke(nativemethodaccessorimpl.java:39)
   at sun.reflect.delegatingmethodaccessorimpl.invoke(delegatingmethodaccessorimpl.java:25)
   at java.lang.reflect.method.invoke(method.java:597)
   at org.eclipse.birt.report.soapengine.processor.abstractbasecomponentprocessor.process(abstractbasecomponentprocessor.java:112)
   at org.eclipse.birt.report.soapengine.endpoint.birtsoapbindingimpl.getupdatedobjects(birtsoapbindingimpl.java:66)
   at sun.reflect.nativemethodaccessorimpl.invoke0(native method)
   at sun.reflect.nativemethodaccessorimpl.invoke(nativemethodaccessorimpl.java:39)
   at sun.reflect.delegatingmethodaccessorimpl.invoke(delegatingmethodaccessorimpl.java:25)
   at java.lang.reflect.method.invoke(method.java:597)
   at org.apache.axis.providers.java.rpcprovider.invokemethod(rpcprovider.java:397)
   at org.apache.axis.providers.java.rpcprovider.processmessage(rpcprovider.java:186)
   at org.apache.axis.providers.java.javaprovider.invoke(javaprovider.java:323)
   at org.apache.axis.strategies.invocationstrategy.visit(invocationstrategy.java:32)
   at org.apache.axis.simplechain.dovisiting(simplechain.java:118)
   at org.apache.axis.simplechain.invoke(simplechain.java:83)
   at org.apache.axis.handlers.soap.soapservice.invoke(soapservice.java:454)
   at org.apache.axis.server.axisserver.invoke(axisserver.java:281)
   at org.apache.axis.transport.http.axisservlet.dopost(axisservlet.java:699)
   at org.eclipse.birt.report.servlet.birtsoapmessagedispatcherservlet.dopost(birtsoapmessagedispatcherservlet.java:265)
   at javax.servlet.http.httpservlet.service(httpservlet.java:727)
   at org.apache.axis.transport.http.axisservletbase.service(axisservletbase.java:327)
   at javax.servlet.http.httpservlet.service(httpservlet.java:820)
   at org.eclipse.birt.report.servlet.birtsoapmessagedispatcherservlet.service(birtsoapmessagedispatcherservlet.java:122)
   at org.eclipse.equinox.http.registry.internal.servletmanager$servletwrapper.service(servletmanager.java:180)
   at org.eclipse.equinox.http.servlet.internal.servletregistration.service(servletregistration.java:61)
   at org.eclipse.equinox.http.servlet.internal.proxyservlet.processalias(proxyservlet.java:126)
   at org.eclipse.equinox.http.servlet.internal.proxyservlet.service(proxyservlet.java:60)
   at javax.servlet.http.httpservlet.service(httpservlet.java:820)
   at org.eclipse.equinox.http.jetty.internal.httpservermanager$internalhttpserviceservlet.service(httpservermanager.java:318)
   at org.mortbay.jetty.servlet.servletholder.handle(servletholder.java:502)
   at org.mortbay.jetty.servlet.servlethandler.handle(servlethandler.java:380)
   at org.mortbay.jetty.servlet.sessionhandler.handle(sessionhandler.java:181)
   at org.mortbay.jetty.handler.contexthandler.handle(contexthandler.java:765)
   at org.mortbay.jetty.handler.handlerwrapper.handle(handlerwrapper.java:152)
   at org.mortbay.jetty.server.handle(server.java:324)
   at org.mortbay.jetty.httpconnection.handlerequest(httpconnection.java:535)
   at org.mortbay.jetty.httpconnection$requesthandler.content(httpconnection.java:880)
   at org.mortbay.jetty.httpparser.parsenext(httpparser.java:748)
   at org.mortbay.jetty.httpparser.parseavailable(httpparser.java:219)
   at org.mortbay.jetty.httpconnection.handle(httpconnection.java:404)
   at org.mortbay.io.nio.selectchannelendpoint.run(selectchannelendpoint.java:409)
   at org.mortbay.thread.queuedthreadpool$poolthread.run(queuedthreadpool.java:520)
can not reproduce at build v20100408
close the bug