Comment 2 for bug 510548

Versions:
Ubuntu: ubuntu karmic 32bits (compiz enabled)
Firefox 3.5.8+build+nobinonly-0ubuntu0.9.10.1
libglib 2.22.3-0ubuntu1

Errors:
(firefox:17750): GLib-WARNING **: g_set_prgname() called multiple times
(firefox:17750): GLib-GObject-WARNING **: invalid unclassed pointer in cast to `GtkObject'
(firefox:17750): GLib-GObject-WARNING **: invalid unclassed pointer in cast to `GtkObject'
(firefox:17750): GLib-GObject-WARNING **: invalid unclassed pointer in cast to `GtkObject'
(firefox:17750): GLib-GObject-WARNING **: instance with invalid (NULL) class pointer
(firefox:17750): GLib-GObject-CRITICAL **: g_signal_handler_disconnect: assertion `G_TYPE_CHECK_INSTANCE (instance)' failed
(firefox:17750): GLib-GObject-WARNING **: instance with invalid (NULL) class pointer
(firefox:17750): GLib-GObject-CRITICAL **: g_signal_handler_disconnect: assertion `G_TYPE_CHECK_INSTANCE (instance)' failed
Segmentation fault

Sometimes I could reproduce the crash:
* Enter gmail and righ-clicked in a link inside a message.
which may rule-out the "flash" related problem...? (as gmail does not include flash objects)

However several times in different sites have crashed.

I'm not sure if the installed plugins are somehow related as when I disabled all of them it didn't crash (I performed few tests).
I activated one by one and test it again... but it was not consistent. However I found that somehow when I deactivate "Flashblock" plugin crashes didn't happen under the same situation, but I can't be 100% sure.

All those errors can be seen also when firefox is restarted after the activation/deactivation of a plugin.