Eclipse Startup Issue: java.lang.ClassNotFoundException: javax.xml.parsers.SAXParserFactory

Today when I started my Eclipse, it simply refused to!!! It simply flashed an alert asking to look into log file. And log file simply said:

!SESSION Dec 31, 2005 10:50:19.810 ---------------------------------------------
eclipse.buildId=I200406251208
java.version=1.3.1_01
java.vendor=Sun Microsystems Inc.
BootLoader constants: OS=win32, ARCH=x86, WS=win32, NL=en_US

!ENTRY org.eclipse.osgi Dec 31, 2005 10:50:19.810
!MESSAGE Error registering XML parser services.
!STACK 0
java.lang.ClassNotFoundException: javax.xml.parsers.SAXParserFactory
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClassInternal(Unknown Source)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at org.eclipse.core.runtime.adaptor.EclipseAdaptor.registerEndorsedXMLParser(EclipseAdaptor.java:272)
at org.eclipse.core.runtime.adaptor.EclipseAdaptor.frameworkStart(EclipseAdaptor.java:253)
at org.eclipse.osgi.framework.internal.core.SystemBundleActivator.start(SystemBundleActivator.java:61)
at org.eclipse.osgi.framework.internal.core.BundleContextImpl$1.run(BundleContextImpl.java:958)
at java.security.AccessController.doPrivileged(Native Method)
at org.eclipse.osgi.framework.internal.core.BundleContextImpl.startActivator(BundleContextImpl.java:954)
at org.eclipse.osgi.framework.internal.core.BundleContextImpl.start(BundleContextImpl.java:937)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.resumeBundles(StartLevelManager.java:553)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.incFWSL(StartLevelManager.java:477)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.doSetStartLevel(StartLevelManager.java:273)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.launch(StartLevelManager.java:243)
at org.eclipse.osgi.framework.internal.core.SystemBundle.resume(SystemBundle.java:166)
at org.eclipse.osgi.framework.internal.core.Framework.launch(Framework.java:425)
at org.eclipse.osgi.framework.internal.core.OSGi.launch(OSGi.java:51)
at org.eclipse.core.runtime.adaptor.EclipseStarter.startup(EclipseStarter.java:216)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:127)
at java.lang.reflect.Method.invoke(Native Method)
at org.eclipse.core.launcher.Main.basicRun(Main.java:183)
at org.eclipse.core.launcher.Main.run(Main.java:644)
at org.eclipse.core.launcher.Main.main(Main.java:628)

!ENTRY org.eclipse.osgi Dec 31, 2005 10:50:19.852
!MESSAGE Startup error
!STACK 1
java.lang.NoClassDefFoundError: org/xml/sax/helpers/DefaultHandler
at java.lang.ClassLoader.defineClass0(Native Method)
at java.lang.ClassLoader.defineClass(Unknown Source)
at java.security.SecureClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.access$100(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClassInternal(Unknown Source)
at org.eclipse.core.runtime.adaptor.PluginConverterImpl.parsePluginInfo(PluginConverterImpl.java:552)
at org.eclipse.core.runtime.adaptor.PluginConverterImpl.fillPluginInfo(PluginConverterImpl.java:111)
at org.eclipse.core.runtime.adaptor.PluginConverterImpl.convertManifest(PluginConverterImpl.java:655)
at org.eclipse.core.runtime.adaptor.EclipseBundleData.generateManifest(EclipseBundleData.java:219)
at org.eclipse.core.runtime.adaptor.EclipseBundleData.loadManifest(EclipseBundleData.java:177)
at org.eclipse.core.runtime.adaptor.EclipseBundleData.getManifest(EclipseBundleData.java:159)
at org.eclipse.core.runtime.adaptor.EclipseBundleData.loadFromManifest(EclipseBundleData.java:266)
at org.eclipse.osgi.framework.internal.defaultadaptor.DefaultBundleData.initializeNewBundle(DefaultBundleData.java:77)
at org.eclipse.osgi.framework.internal.defaultadaptor.DefaultAdaptor$1.begin(DefaultAdaptor.java:451)
at org.eclipse.osgi.framework.internal.core.Framework.installWorkerPrivileged(Framework.java:746)
at org.eclipse.osgi.framework.internal.core.Framework$2.run(Framework.java:664)
at java.security.AccessController.doPrivileged(Native Method)
at org.eclipse.osgi.framework.internal.core.Framework.installWorker(Framework.java:715)
at org.eclipse.osgi.framework.internal.core.Framework.installBundle(Framework.java:659)
at org.eclipse.osgi.framework.internal.core.BundleContextImpl.installBundle(BundleContextImpl.java:219)
at org.eclipse.core.runtime.adaptor.EclipseStarter.installBundles(EclipseStarter.java:800)
at org.eclipse.core.runtime.adaptor.EclipseStarter.loadBasicBundles(EclipseStarter.java:429)
at org.eclipse.core.runtime.adaptor.EclipseStarter.startup(EclipseStarter.java:222)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:127)
at java.lang.reflect.Method.invoke(Native Method)
at org.eclipse.core.launcher.Main.basicRun(Main.java:183)
at org.eclipse.core.launcher.Main.run(Main.java:644)
at org.eclipse.core.launcher.Main.main(Main.java:628)

!ENTRY org.eclipse.osgi Dec 31, 2005 10:50:19.863
!MESSAGE Bundle initial@reference:file:c:/eclipse0/plugins/org.eclipse.core.runtime_3.0.0/ [192] was not resolved.

I checked the classpath. Everything seemed same as before. So, what to do? I simply picked up the Eclipse from a collegue's machine and started it. and What?!!! It bombed again, saying the same old story. Then I checked that Eclipse was not working on his machine as well. So what to do now?
Then it occured to me that something else is interrupting Eclipse to start; something that is a new installed entity for both the machines. Both of us had installed Oracle 9i client a day before, it was the first time that the Eclipse was being restarted. So, I simply modified the 'path' entry - remove

C:\Program Files\Oracle\jre\1.3.1\bin;C:\Program Files\Oracle\jre\1.1.8\bin;

from the path, and restart Eclipse. It works again!