ROOT freezes on OS X

Hello,
I have a student with the following setup:
OS X 10.8.2
ROOT 5.34.04
XQuartz (unsure of version)

When loading any graphics: either starting root with the splash screen or creating a canvas when starting root with -l option, ROOT just hangs and becomes unresponsive. No error messages unfortunately.

Anyone have any ideas?

Does Xquartz start ? do you see the big X on the dock ?