Ok Milan, this is (i think) a very detailed info:

'sudo dbus-monitor --system' output:
------------------------------------------------------------------------------------------------------------------
signal sender=org.freedesktop.DBus -> dest=:1.61 serial=2 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=NameAcquired
   string ":1.61"
method call sender=:1.53 -> dest=:1.61 serial=278 path=/; interface=org.freedesktop.DBus.Introspectable; member=Introspect
signal sender=org.freedesktop.DBus -> dest=(null destination) serial=7 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=NameOwnerChanged
   string ":1.62"
   string ""
   string ":1.62"
signal sender=org.freedesktop.DBus -> dest=(null destination) serial=8 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=NameOwnerChanged
   string "org.freedesktop.SystemToolsBackends"
   string ""
   string ":1.62"
signal sender=org.freedesktop.DBus -> dest=(null destination) serial=9 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=NameOwnerChanged
   string ":1.63"
   string ""
   string ":1.63"
------------------------------------------------------------------------------------------------------------------

'sudo G_DEBUG="fatal_criticals" gdb system-tools-backends' output:
------------------------------------------------------------------------------------------------------------------
jaime@Sion:~$ sudo G_DEBUG="fatal_criticals" gdb system-tools-backends
[sudo] password for jaime: 
GNU gdb (GDB) 7.0-ubuntu
Copyright (C) 2009 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "i486-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /usr/sbin/system-tools-backends...Reading symbols from /usr/lib/debug/usr/sbin/system-tools-backends...done.
(no debugging symbols found)...done.
(gdb) break get_destination
Breakpoint 1 at 0x804b296: file dispatcher.c, line 297.
(gdb) run
Starting program: /usr/sbin/system-tools-backends 
[Thread debugging using libthread_db enabled]

Breakpoint 1, get_destination (message=0x80567e8) at dispatcher.c:297
297	dispatcher.c: No such file or directory.
	in dispatcher.c
(gdb) print arr[0]
Cannot access memory at address 0x0
(gdb) next
294	in dispatcher.c
(gdb) print arr[0]
Cannot access memory at address 0x0
(gdb) next
297	in dispatcher.c
(gdb) print arr[0]
Cannot access memory at address 0x0
(gdb) next
300	in dispatcher.c
(gdb) print arr[0]
Cannot access memory at address 0x0
(gdb) next
304	in dispatcher.c
(gdb) print arr[0]
$1 = (gchar *) 0x0
(gdb) print arr[1]
$2 = (gchar *) 0x0
(gdb) print arr[2]
$3 = (gchar *) 0x0
(gdb) print arr[3]
$4 = (gchar *) 0x11 <Address 0x11 out of bounds>
(gdb) print arr[4]
$5 = (gchar *) 0x2f <Address 0x2f out of bounds>
(gdb) next
309	in dispatcher.c
(gdb) print arr[0]
$6 = (gchar *) 0x0
(gdb) print arr[1]
$7 = (gchar *) 0x0
(gdb) print arr[2]
$8 = (gchar *) 0x0
(gdb) print arr[3]
$9 = (gchar *) 0x11 <Address 0x11 out of bounds>
(gdb) print arr[4]
$10 = (gchar *) 0x2f <Address 0x2f out of bounds>
(gdb) next
311	in dispatcher.c
(gdb) print arr[0]
$11 = (gchar *) 0x805dd58 "ble"
(gdb) print arr[1]
$12 = (gchar *) 0x0
(gdb) print arr[2]
$13 = (gchar *) 0x0
(gdb) print arr[3]
$14 = (gchar *) 0x11 <Address 0x11 out of bounds>
(gdb) print arr[4]
$15 = (gchar *) 0x2f <Address 0x2f out of bounds>
(gdb) next
312	in dispatcher.c
(gdb) print arr[0]
$16 = (gchar *) 0x805dd58 "ble"
(gdb) print arr[1]
$17 = (gchar *) 0x0
(gdb) print arr[2]
$18 = (gchar *) 0x0
(gdb) print arr[3]
$19 = (gchar *) 0x11 <Address 0x11 out of bounds>
(gdb) print arr[4]
$20 = (gchar *) 0x2f <Address 0x2f out of bounds>
(gdb) next
dispatch_stb_message (dispatcher=<value optimized out>, message=0x80567e8, 
    serial=<value optimized out>) at dispatcher.c:425
425	in dispatcher.c
(gdb) print arr[0]
No symbol "arr" in current context.
(gdb) print arr[1]
No symbol "arr" in current context.
(gdb) print arr[2]
No symbol "arr" in current context.
(gdb) print arr[3]
No symbol "arr" in current context.
(gdb) print arr[4]
No symbol "arr" in current context.
(gdb) next
422	in dispatcher.c
(gdb) print arr[0]
No symbol "arr" in current context.
(gdb) print arr[1]
No symbol "arr" in current context.
(gdb) print arr[2]
No symbol "arr" in current context.
(gdb) print arr[3]
No symbol "arr" in current context.
(gdb) print arr[4]
No symbol "arr" in current context.
(gdb) next
425	in dispatcher.c
(gdb) print arr[0]
No symbol "arr" in current context.
(gdb) print arr[1]
No symbol "arr" in current context.
(gdb) print arr[2]
No symbol "arr" in current context.
(gdb) print arr[3]
No symbol "arr" in current context.
(gdb) print arr[4]
No symbol "arr" in current context.
(gdb) next
427	in dispatcher.c
(gdb) print arr[0]
No symbol "arr" in current context.
(gdb) print arr[1]
No symbol "arr" in current context.
(gdb) print arr[2]
No symbol "arr" in current context.
(gdb) print arr[3]
No symbol "arr" in current context.
(gdb) print arr[4]
No symbol "arr" in current context.
(gdb) next

** CRITICAL **: Could not get a valid destination, original one was: /
aborting...

Program received signal SIGABRT, Aborted.
0x00da5422 in __kernel_vsyscall ()
(gdb) print arr[0]
No symbol "arr" in current context.
(gdb) print arr[1]
No symbol "arr" in current context.
(gdb) print arr[2]
No symbol "arr" in current context.
(gdb) print arr[3]
No symbol "arr" in current context.
(gdb) print arr[4]
No symbol "arr" in current context.
(gdb) 

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