I built it from the apt-get retrieved source and got the following backtrace; the interesting bit is:

#21 0x00000000004c94e1 in amide_log_handler (log_domain=<value optimised out>, log_level=<value optimised out>, message=0x92a4b0 "Extension stl not recognized on file: /discs/more/3dbrot/prob/h.stl\nGuessing File Type", user_data=0x926010) at amide.c:92

which shows it was trying to give me an error dialog telling me I'd foolishly forgot to give it the right type of file,
and b)

#4  0x00007ffff72cec05 in gtk_dialog_set_alternative_button_order () from /usr/lib/libgtk-x11-2.0.so.0
#5  0x00007fffecdc604a in Oxygen::DialogEngine::registerWidget(_GtkWidget*) () from /usr/lib/gtk-2.0/2.10.0/engines/liboxygen-gtk.so

so it is going through the oxygen theme - but I'm not sure whether it's Amide or Oxygen's fault (which would
probably be ironic).

(gdb) where
#0  0x00007ffff591ab45 in raise (sig=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:64
#1  0x00007ffff591e496 in abort () at abort.c:92
#2  0x00007ffff6156a52 in g_logv () from /lib/libglib-2.0.so.0
#3  0x00007ffff6156adf in g_log () from /lib/libglib-2.0.so.0
#4  0x00007ffff72cec05 in gtk_dialog_set_alternative_button_order () from /usr/lib/libgtk-x11-2.0.so.0
#5  0x00007fffecdc604a in Oxygen::DialogEngine::registerWidget(_GtkWidget*) () from /usr/lib/gtk-2.0/2.10.0/engines/liboxygen-gtk.so
#6  0x00007fffece3b47d in ?? () from /usr/lib/gtk-2.0/2.10.0/engines/liboxygen-gtk.so
#7  0x00007ffff7475006 in ?? () from /usr/lib/libgtk-x11-2.0.so.0
#8  0x00007ffff747a89c in ?? () from /usr/lib/libgtk-x11-2.0.so.0
#9  0x00007ffff66457fc in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#10 0x00007ffff66567e3 in ?? () from /usr/lib/libgobject-2.0.so.0
#11 0x00007ffff6660258 in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#12 0x00007ffff666041f in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
#13 0x00007ffff746ccce in gtk_widget_realize () from /usr/lib/libgtk-x11-2.0.so.0
#14 0x00007ffff74772e8 in ?? () from /usr/lib/libgtk-x11-2.0.so.0
#15 0x00007ffff66457fc in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#16 0x00007ffff66567e3 in ?? () from /usr/lib/libgobject-2.0.so.0
#17 0x00007ffff6660258 in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#18 0x00007ffff666041f in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
#19 0x00007ffff746dc86 in gtk_widget_show () from /usr/lib/libgtk-x11-2.0.so.0
#20 0x00007ffff72ce968 in gtk_dialog_run () from /usr/lib/libgtk-x11-2.0.so.0
#21 0x00000000004c94e1 in amide_log_handler (log_domain=<value optimised out>, log_level=<value optimised out>, message=0x92a4b0 "Extension stl not recognized on file: /discs/more/3dbrot/prob/h.stl\nGuessing File Type", user_data=0x926010) at amide.c:92
#22 0x00007ffff615673c in g_logv () from /lib/libglib-2.0.so.0
#23 0x00007ffff6156adf in g_log () from /lib/libglib-2.0.so.0
#24 0x00000000004e9dbc in amitk_data_set_import_file (method=<value optimised out>, submethod=<value optimised out>, filename=0x823b00 "/discs/more/3dbrot/prob/h.stl", preferences=0x926010, update_func=<value optimised out>, update_data=<value optimised out>)
    at amitk_data_set.c:1506
#25 0x00000000004c9720 in main (argc=1, argv=0x7fffffffdff8) at amide.c:205