pygtkhelpers makes use of relative imports in debug/__init__.py, utils.py and delegates.py. Uses try..except..finally in debug/console.py. And conditional expressions in debug/dialogs.py and ui/objectlist.py. All of these features require Python 2.5 or later. Thanks, James Reproducible: Always
Looking further... The unstated pygtk dependency requires at least 2.6 in both versions in the tree anyway, so even 2.5 support in pygtkhelpers seems quite pointless to me.
Fixed.