Firefox zeitgeist extension causes the browser to freeze when opening any file via download window

Steps to reproduce:
1) Open any site with link to PDF / RTF / ODT (any kind of file firefox cannot open), click that link and choose "open with" instead of "save into the place"
2) See firefox freezed

Reproduced on FF 7.0.1, zeitgeist extension compiled from source (the trunk version)

Please see the log:
(firefox:4653): GLib-GObject-WARNING **: cannot register existing type `ZeitgeistEvent'
(firefox:4653): GLib-CRITICAL **: g_once_init_leave: assertion `initialization_value != 0' failed
(firefox:4653): GLib-GObject-CRITICAL **: g_object_new: assertion `G_TYPE_IS_OBJECT (object_type)' failed
(firefox:4653): GLib-GObject-WARNING **: cannot register existing type `ZeitgeistSubject'
(firefox:4653): GLib-CRITICAL **: g_once_init_leave: assertion `initialization_value != 0' failed
(firefox:4653): GLib-GObject-CRITICAL **: g_object_new: assertion `G_TYPE_IS_OBJECT (object_type)' failed