description:
[smoke]exception keep throwing and block to edit and preview data set

build number: 2.5.2.v20100125-0630

steps to reproduce:
1, new a data set
2, preview or edit the dataset

actual result:
exception keep throwing and block to edit and preview data set

error log:
org.eclipse.birt.report.designer.core.runtime.guiexception: caused by java.lang.reflect.invocationtargetexception.
at org.eclipse.birt.report.designer.core.runtime.guiexception.createguiexception(guiexception.java:78)
at org.eclipse.birt.report.designer.internal.ui.util.exceptionhandler.handle(exceptionhandler.java:169)
at org.eclipse.birt.report.designer.internal.ui.util.exceptionhandler.handle(exceptionhandler.java:150)
at org.eclipse.birt.report.designer.internal.ui.util.exceptionhandler.handle(exceptionhandler.java:89)
at org.eclipse.birt.report.designer.data.ui.dataset.resultsetpreviewpage.updateresultsprocess(resultsetpreviewpage.java:543)
at org.eclipse.birt.report.designer.data.ui.dataset.resultsetpreviewpage.access$1(resultsetpreviewpage.java:409)
at org.eclipse.birt.report.designer.data.ui.dataset.resultsetpreviewpage$4.runinuithread(resultsetpreviewpage.java:263)
at org.eclipse.ui.progress.uijob$1.run(uijob.java:95)
at org.eclipse.swt.widgets.runnablelock.run(runnablelock.java:35)
at org.eclipse.swt.widgets.synchronizer.runasyncmessages(synchronizer.java:134)
at org.eclipse.swt.widgets.display.runasyncmessages(display.java:3872)
at org.eclipse.swt.widgets.display.readanddispatch(display.java:3493)
at org.eclipse.jface.window.window.runeventloop(window.java:825)
at org.eclipse.jface.window.window.open(window.java:801)
at org.eclipse.birt.report.designer.ui.dialogs.basedialog.open(basedialog.java:110)
at org.eclipse.birt.report.designer.data.ui.actions.newdatasetaction.editdataset(newdatasetaction.java:237)
at org.eclipse.birt.report.designer.data.ui.actions.newdatasetaction.createnewdataset(newdatasetaction.java:196)
at org.eclipse.birt.report.designer.data.ui.actions.newdatasetaction.run(newdatasetaction.java:181)
at org.eclipse.jface.action.action.runwithevent(action.java:498)
at org.eclipse.jface.action.actioncontributionitem.handlewidgetselection(actioncontributionitem.java:584)
at org.eclipse.jface.action.actioncontributionitem.access$2(actioncontributionitem.java:501)
at org.eclipse.jface.action.actioncontributionitem$5.handleevent(actioncontributionitem.java:411)
at org.eclipse.swt.widgets.eventtable.sendevent(eventtable.java:84)
at org.eclipse.swt.widgets.widget.sendevent(widget.java:1003)
at org.eclipse.swt.widgets.display.rundeferredevents(display.java:3897)
at org.eclipse.swt.widgets.display.readanddispatch(display.java:3490)
at org.eclipse.ui.internal.workbench.runeventloop(workbench.java:2405)
at org.eclipse.ui.internal.workbench.runui(workbench.java:2369)
at org.eclipse.ui.internal.workbench.access$4(workbench.java:2221)
at org.eclipse.ui.internal.workbench$5.run(workbench.java:500)
at org.eclipse.core.databinding.observable.realm.runwithdefault(realm.java:332)
at org.eclipse.ui.internal.workbench.createandrunworkbench(workbench.java:493)
at org.eclipse.ui.platformui.createandrunworkbench(platformui.java:149)
at org.eclipse.ui.internal.ide.application.ideapplication.start(ideapplication.java:113)
at org.eclipse.equinox.internal.app.eclipseapphandle.run(eclipseapphandle.java:194)
at org.eclipse.core.runtime.internal.adaptor.eclipseapplauncher.runapplication(eclipseapplauncher.java:110)
at org.eclipse.core.runtime.internal.adaptor.eclipseapplauncher.start(eclipseapplauncher.java:79)
at org.eclipse.core.runtime.adaptor.eclipsestarter.run(eclipsestarter.java:368)
at org.eclipse.core.runtime.adaptor.eclipsestarter.run(eclipsestarter.java:179)
at sun.reflect.nativemethodaccessorimpl.invoke0(native method)
at sun.reflect.nativemethodaccessorimpl.invoke(unknown source)
at sun.reflect.delegatingmethodaccessorimpl.invoke(unknown source)
at java.lang.reflect.method.invoke(unknown source)
at org.eclipse.equinox.launcher.main.invokeframework(main.java:559)
at org.eclipse.equinox.launcher.main.basicrun(main.java:514)
at org.eclipse.equinox.launcher.main.run(main.java:1311)
caused by: java.lang.reflect.invocationtargetexception
at org.eclipse.jface.operation.modalcontext.run(modalcontext.java:421)
at org.eclipse.jface.dialogs.progressmonitordialog.run(progressmonitordialog.java:507)
at org.eclipse.birt.report.designer.data.ui.dataset.resultsetpreviewpage.updateresultsprocess(resultsetpreviewpage.java:539)
... 41 more
caused by: java.lang.nullpointerexception
at org.eclipse.birt.report.data.adapter.impl.datarequestsessionimpl.definedataset(datarequestsessionimpl.java:167)
at org.eclipse.birt.report.designer.data.ui.util.datasetprovider.execute(datasetprovider.java:455)
at org.eclipse.birt.report.designer.data.ui.util.datasetexecutorhelper.execute(datasetexecutorhelper.java:148)
at org.eclipse.birt.report.designer.data.ui.dataset.resultsetpreviewpage.executeprocess(resultsetpreviewpage.java:372)
at org.eclipse.birt.report.designer.data.ui.dataset.resultsetpreviewpage.access$2(resultsetpreviewpage.java:294)
at org.eclipse.birt.report.designer.data.ui.dataset.resultsetpreviewpage$5.run(resultsetpreviewpage.java:474)
at org.eclipse.jface.operation.modalcontext$modalcontextthread.run(modalcontext.java:121)
fixed.
verified in 2.5.2 v20100126-0630 build, closed