android - Eclipse: java.lang.RuntimeException: Application “org.eclipse.ui.ide.workbench” could not be found in the registry -

iam using helios eclipse (eclipse-sdk-3.6.1-win32).
update helps > check of updates have updated checking all. (most of them plugin related android)
after completion of updates, asked me restart eclipse. after that, when ever start eclipse shows error. shows following dialog

an error has occurred. see log file d:\eclipse-sdk-3.6.1-win32\eclipse\configuration\11003434.log. 

that log

!session 2011-05-11 12:06:34.453 ----------------------------------------------- eclipse.buildid=m20110210-1200 java.version=1.6.0_24 java.vendor=sun microsystems inc. bootloader constants: os=win32, arch=x86, ws=win32, nl=en_us command-line arguments:  -os win32 -ws win32 -arch x86  !entry org.eclipse.osgi 2 0 2011-05-11 12:06:36.593 !message 1 or more bundles not resolved because following root constraints not resolved: !subentry 1 org.eclipse.osgi 2 0 2011-05-11 12:06:36.593   !entry org.eclipse.osgi 4 0 2011-05-11 12:06:36.687 !message application error !stack 1 java.lang.runtimeexception: application "org.eclipse.ui.ide.workbench" not found in registry. applications available are: org.eclipse.equinox.app.error, org.eclipse.equinox.p2.director.app.application, org.eclipse.equinox.p2.director, org.eclipse.equinox.p2.garbagecollector.application, org.eclipse.equinox.p2.publisher.installpublisher, org.eclipse.equinox.p2.publisher.eclipsegenerator, org.eclipse.equinox.p2.publisher.productpublisher, org.eclipse.equinox.p2.publisher.featuresandbundlespublisher, org.eclipse.equinox.p2.repository.repo2runnable, org.eclipse.equinox.p2.repository.metadataverifier, org.eclipse.equinox.p2.artifact.repository.mirrorapplication, org.eclipse.equinox.p2.metadata.repository.mirrorapplication, org.eclipse.equinox.p2.updatesite.updatesitepublisher, org.eclipse.equinox.p2.publisher.updatesitepublisher, org.eclipse.equinox.p2.publisher.categorypublisher, org.eclipse.pde.junit.runtime.uitestapplication, org.eclipse.pde.junit.runtime.legacytestapplication, org.eclipse.pde.junit.runtime.coretestapplication, org.eclipse.pde.junit.runtime.coretestapplicationnonmain, org.eclipse.pde.junit.runtime.nonuithreadtestapplication, org.eclipse.update.core.standaloneupdate, org.eclipse.update.core.siteoptimizer, org.eclipse.ant.core.antrunner, org.eclipse.equinox.p2.metadata.generator.eclipsegenerator, org.eclipse.equinox.p2.reconciler.application, org.eclipse.help.base.infocenterapplication, org.eclipse.help.base.helpapplication, org.eclipse.help.base.indextool, org.eclipse.jdt.apt.core.aptbuild, org.eclipse.jdt.core.javacodeformatter, org.eclipse.pde.build.build.     @ org.eclipse.equinox.internal.app.eclipseappcontainer.startdefaultapp(eclipseappcontainer.java:248)     @ org.eclipse.equinox.internal.app.mainapplicationlauncher.run(mainapplicationlauncher.java:29)     @ org.eclipse.core.runtime.internal.adaptor.eclipseapplauncher.runapplication(eclipseapplauncher.java:110)     @ org.eclipse.core.runtime.internal.adaptor.eclipseapplauncher.start(eclipseapplauncher.java:79)     @ org.eclipse.core.runtime.adaptor.eclipsestarter.run(eclipsestarter.java:369)     @ org.eclipse.core.runtime.adaptor.eclipsestarter.run(eclipsestarter.java:179)     @ sun.reflect.nativemethodaccessorimpl.invoke0(native method)     @ sun.reflect.nativemethodaccessorimpl.invoke(unknown source)     @ sun.reflect.delegatingmethodaccessorimpl.invoke(unknown source)     @ java.lang.reflect.method.invoke(unknown source)     @ org.eclipse.equinox.launcher.main.invokeframework(main.java:620)     @ org.eclipse.equinox.launcher.main.basicrun(main.java:575)     @ org.eclipse.equinox.launcher.main.run(main.java:1408) 

i didn't understand anything.
can me in this.
i'm stuck

did try running eclipse.exe -clean?

any cached data used osgi framework , eclipse runtime wiped clean. clean caches used store bundle dependency resolution , eclipse extension registry data. using option force eclipse reinitialize these caches.