When you see an empty dialog just after the splash screen, first check the .log file under workspace/.metadata/
if it is a xul error, which probably is, then do this:
sudo apt-get install xulrunner
append to eclipse.ini
-Dorg.eclipse.swt.browser.XULRunnerPath=/usr/lib/xulrunner/xulrunner
(taken from : http://sandakith.wordpress.com/2008/07/11/eclipse-ganymede-startup-problem-in-ubuntu-orgeclipseswtswterror-xpcom-erro/)
Remember: the -D… stuff goes last in eclipse.ini