Eclipse won't start java.lang.NoClassDefFoundError: org/w3c/dom/ElementTraversal

[Dave-B]

Installed Eclipse from Software centre.

Expected result:
Run it and use it.

Actual result:
Run it and get an error dialog, prompting me to look at the log file (attached), which has the error "java.lang.NoClassDefFoundError: org/w3c/dom/ElementTraversal".

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: eclipse 3.7.2-1
ProcVersionSignature: Ubuntu 3.2.0-24.39-generic 3.2.16
Uname: Linux 3.2.0-24-generic x86_64
ApportVersion: 2.0.1-0ubuntu7
Architecture: amd64
Date: Wed May 30 11:50:13 2012
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425)
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=en_GB:en
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SourcePackage: eclipse
UpgradeStatus: No upgrade log present (probably fresh install)