I added the following:
gcin-dbgsym
libgtk2.0-0-dbgsym
libglib2.0-cil-dbgsym
libglib2.0-0-dbgsym

I didn't add this package, because it's not in apt.
libgtk2.0-cil-dbgs

The debugging info still looks the same... 
xxx@ubuntu:/usr/lib/gnome-do$ mono --debug Do.exe
Stacktrace:

  at (wrapper managed-to-native) Gtk.IMContext.gtk_im_context_filter_keypress (intptr,intptr) <0x0005c>
  at (wrapper managed-to-native) Gtk.IMContext.gtk_im_context_filter_keypress (intptr,intptr) <0xffffffff>
  at Gtk.IMContext.FilterKeypress (Gdk.EventKey) <0x00057>
  at Do.Core.Controller.OnInputKeyPressEvent (Gdk.EventKey) <0x0002b>
  at Do.Core.Controller.KeyPressWrap (Gdk.EventKey) <0x002c7>
  at Do.Interface.ClassicWindow.OnKeyPressEvent (Gdk.EventKey) <0x0001f>
  at Gtk.Widget.keypressevent_cb (intptr,intptr) <0x00082>
  at (wrapper native-to-managed) Gtk.Widget.keypressevent_cb (intptr,intptr) <0xffffffff>
  at (wrapper managed-to-native) Gtk.Application.gtk_main () <0x0004d>
  at (wrapper managed-to-native) Gtk.Application.gtk_main () <0xffffffff>
  at Gtk.Application.Run () <0x0000b>
  at Do.Do.Main (string[]) <0x002af>
  at (wrapper runtime-invoke) Do.Do.runtime_invoke_void_string[] (object,intptr,intptr,intptr) <0xffffffff>

Native stacktrace:

	mono [0x429e65]
	mono [0x44ba7d]
	/lib/libpthread.so.0 [0x7fa0e1fab080]
	/usr/lib/gcin/libgcin-im-client.so.1(gcin_im_client_forward_key_press+0x24) [0x7fa0d7b745f9]
	/usr/lib/gtk-2.0/2.10.0/immodules/im-gcin.so [0x7fa0d7d78fe3]
	[0x415fd7cc]

Debug info from gdb:

(no debugging symbols found)
[Thread debugging using libthread_db enabled]
[New Thread 0x7fa0e2c8f730 (LWP 8430)]
[New Thread 0x7fa0d57a2950 (LWP 8434)]
[New Thread 0x7fa0e089e950 (LWP 8432)]
[New Thread 0x7fa0e2c98950 (LWP 8431)]
0x00007fa0e1fa9edb in read () from /lib/libpthread.so.0
  4 Thread 0x7fa0e2c98950 (LWP 8431)  0x00007fa0e1faa7e1 in nanosleep () from /lib/libpthread.so.0
  3 Thread 0x7fa0e089e950 (LWP 8432)  0x00007fa0e1fa72e9 in pthread_cond_wait@@GLIBC_2.3.2 ()
   from /lib/libpthread.so.0
  2 Thread 0x7fa0d57a2950 (LWP 8434)  0x00007fa0e1faa7e1 in nanosleep () from /lib/libpthread.so.0
  1 Thread 0x7fa0e2c8f730 (LWP 8430)  0x00007fa0e1fa9edb in read () from /lib/libpthread.so.0

Thread 4 (Thread 0x7fa0e2c98950 (LWP 8431)):
#0  0x00007fa0e1faa7e1 in nanosleep () from /lib/libpthread.so.0
#1  0x0000000000503be2 in ?? ()
#2  0x00007fa0e1fa33ba in start_thread () from /lib/libpthread.so.0
#3  0x00007fa0e1a8afcd in clone () from /lib/libc.so.6
#4  0x0000000000000000 in ?? ()

Thread 3 (Thread 0x7fa0e089e950 (LWP 8432)):
#0  0x00007fa0e1fa72e9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0
#1  0x0000000000506815 in ?? ()
#2  0x0000000000508f8f in ?? ()
#3  0x000000000052123d in ?? ()
#4  0x0000000000496d33 in ?? ()
#5  0x00000000004b52d3 in ?? ()
#6  0x000000000051d81b in ?? ()
#7  0x000000000053a1c2 in ?? ()
#8  0x00007fa0e1fa33ba in start_thread () from /lib/libpthread.so.0
#9  0x00007fa0e1a8afcd in clone () from /lib/libc.so.6
#10 0x0000000000000000 in ?? ()

Thread 2 (Thread 0x7fa0d57a2950 (LWP 8434)):
#0  0x00007fa0e1faa7e1 in nanosleep () from /lib/libpthread.so.0
#1  0x000000000051cc9b in ?? ()
#2  0x00000000004b48fe in ?? ()
#3  0x00000000415fcad8 in ?? ()
#4  0x0000000002d50890 in ?? ()
#5  0x0000000002d50890 in ?? ()
#6  0x00007fa0d99a7f80 in ?? ()
#7  0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7fa0e2c8f730 (LWP 8430)):
#0  0x00007fa0e1fa9edb in read () from /lib/libpthread.so.0
#1  0x0000000000429f6c in ?? ()
#2  0x000000000044ba7d in ?? ()
#3  <signal handler called>
#4  0x00007fa0d7b745f9 in gcin_im_client_forward_key_press ()
   from /usr/lib/gcin/libgcin-im-client.so.1
#5  0x00007fa0d7d78fe3 in gtk_im_context_gcin_filter_keypress ()
   from /usr/lib/gtk-2.0/2.10.0/immodules/im-gcin.so
#6  0x00000000415fd7cc in ?? ()
#7  0x00007fffeacabc70 in ?? ()
#8  0x00007fffeacab090 in ?? ()
#9  0x0000000000000000 in ?? ()
#0  0x00007fa0e1fa9edb in read () from /lib/libpthread.so.0

=================================================================
Got a SIGSEGV while executing native code. This usually indicates
a fatal error in the mono runtime or one of the native libraries 
used by your application.
=================================================================

Aborted

This is what I install now.
gnome-do_0.8.0-0~intrepid~ppa1_amd64.deb
Maybe is there a debug version of gnome-do I should install?