There is a more complete patch at http://bugzilla.gnome.org/attachment.cgi?id=132271&action=view , which is apparently already commited in the upstream version. It applies fine, though the file locations are a bit different in Ubuntu, and also solves the crash, at least for me.
Looks like comment #32 here: http:// bugzilla. gnome.org/ show_bug. cgi?id= 577649# c32 and its followups seem to fix the problem. When I remove the inheritance of gobject in GnomeURLopener, the crash goes away.
There is a more complete patch at http:// bugzilla. gnome.org/ attachment. cgi?id= 132271& action= view , which is apparently already commited in the upstream version. It applies fine, though the file locations are a bit different in Ubuntu, and also solves the crash, at least for me.