There is a problem running Eclipse Europe (3.3) in Ubuntu (Karmic Koala). Once Eclipse starts, JVM crashes and workspace does not appears. You can solve this issue simply by inserting following directive into eclipse.ini file.
-Dorg.eclipse.swt.browser.XULRunnerPath=/dev/null
If you are using Adobe Flex Builder 3 (Alpha version), you must put this directive to the last line of file Adobe_Flex_builder.sh:
"${ECLIPSE_LOCATION}"/eclipse -vmargs -Xmx512M -Dorg.eclipse.swt.browser.XULRunnerPath=/dev/null