Well, another data point. If I don't export the SHLIB_PATH environment variable pointing to /opt/gtk2.6, which contains the GTK2.6.8 bits swinstalled from the GTK2.6.8 depot that I got by following the links from
www.hp.com/go/firefox, then FireFox3 complains about missing out on gtk stuff(not unexpected), but it does come up without crashing. So, clearly something is missing from either the depot I used to load GTK2.6.8, or its use depends on some other shared library that is out of date on my system. Any idea what that might be?