Just add the following line to your ECLIPSE_UMPACKED_DIR/eclipse.ini.
-Dorg.eclipse.swt.browser.XULRunnerPath=/dev/null
I found the error message just running
./eclipse -consolelog
Then, it took me direct to a problem related to firefox...
marcello@survival:~/development/ide/eclipse3.4$ xulrunner -v
Mozilla XULRunner 1.9b5 - 2008041514
https://bugs.eclipse.org/bugs/show_bug.cgi?id=213194
https://bugs.eclipse.org/bugs/show_bug.cgi?id=235020
I had spent around 2 hours to find the correct error message...
have fun!
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Marcello de Sales SF, CA. Ubuntu 8.04 64bit on HP Pavilion dv9500 Intel®Core™2 Duo T7500 @ 2.2GHz 4MB lv2 nVidia 8600M GS 512MB 4GB RAM ATA 240GB DVDRAM+Lightscribe Realtek RTL8111/8168B Gigabit Ethernet PRO/Wireless 4965 AGN Mic+WebCam 17"