I tried with a new profile => I get the same error than befor when trying to read the damned mail:

jeff@jeff-laptop:~$ mozilla-thunderbird -ProfileManager
DOUBLE-CLICK: 400 --> -1 THRESHOLD: 8 --> -1 DOUBLE-CLICK: 400 --> -1 THRESHOLD: 8 --> -1 Segmentation fault

I keep using the new profile for the following tests.

I tried to follow the instructions of the firefox debugging guide, but i didn't find an equivalent of firefox-dbg package for thunderbird so i installed firefox-dbg.

there are the results of the backtrace generation test found here: https://wiki.ubuntu.com/MozillaTeam/Bugs:

[code]
jeff@jeff-laptop:~$ mozilla-thunderbird -g 2>&1 | tee ~/Desktop/gdb-thunderbird.log
/usr/lib/mozilla-thunderbird/run-mozilla.sh -g /usr/lib/mozilla-thunderbird/mozilla-thunderbird-bin
MOZILLA_FIVE_HOME=/usr/lib/mozilla-thunderbird
  LD_LIBRARY_PATH=/usr/lib/mozilla-thunderbird:/usr/lib/mozilla-thunderbird/plugins:/usr/lib/mre/mre
DISPLAY=:0.0
DYLD_LIBRARY_PATH=/usr/lib/mozilla-thunderbird:/usr/lib/mre/mre
     LIBRARY_PATH=/usr/lib/mozilla-thunderbird:/usr/lib/mozilla-thunderbird/components:/usr/lib/mre/mre
       SHLIB_PATH=/usr/lib/mozilla-thunderbird:/usr/lib/mre/mre
          LIBPATH=/usr/lib/mozilla-thunderbird:/usr/lib/mre/mre
       ADDON_PATH=/usr/lib/mozilla-thunderbird
      MOZ_PROGRAM=/usr/lib/mozilla-thunderbird/mozilla-thunderbird-bin
      MOZ_TOOLKIT=
        moz_debug=1
     moz_debugger=
/usr/bin/gdb /usr/lib/mozilla-thunderbird/mozilla-thunderbird-bin -x /tmp/mozargs.Om6930
GNU gdb 6.6-debian
Copyright (C) 2006 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "i486-linux-gnu"...
(no debugging symbols found)
Using host libthread_db library "/lib/tls/i686/cmov/libthread_db.so.1".
(gdb) run
Starting program: /usr/lib/mozilla-thunderbird/mozilla-thunderbird-bin 
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
[Thread debugging using libthread_db enabled]
[New Thread -1220781296 (LWP 6936)]
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
[New Thread -1223496816 (LWP 6939)]
[New Thread -1235465328 (LWP 6940)]
[New Thread -1257636976 (LWP 6942)]
DOUBLE-CLICK: 400 --> -1 THRESHOLD: 8 --> -1 [New Thread -1272022128 (LWP 6945)]
[New Thread -1280414832 (LWP 6946)]
[New Thread -1290798192 (LWP 6948)]
[Thread -1280414832 (LWP 6946) exited]

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread -1220781296 (LWP 6936)]
0xb54e654d in ?? () from /usr/lib/mozilla-thunderbird/components/libgklayout.so
(gdb) bt full
#0  0xb54e654d in ?? ()
   from /usr/lib/mozilla-thunderbird/components/libgklayout.so
No symbol table info available.
#1  0x0903ef10 in ?? ()
No symbol table info available.
#2  0xbf9b4a9c in ?? ()
No symbol table info available.
#3  0x0903ef10 in ?? ()
No symbol table info available.
#4  0x00000001 in ?? ()
No symbol table info available.
#5  0xbf9b4ae8 in ?? ()
No symbol table info available.
#6  0x00000000 in ?? ()
No symbol table info available.
(gdb) thread apply all backtrace full

Thread 7 (Thread -1290798192 (LWP 6948)):
#0  0xffffe410 in __kernel_vsyscall ()
No symbol table info available.
#1  0xb7e1684c in pthread_cond_timedwait@@GLIBC_2.3.2 ()
   from /lib/tls/i686/cmov/libpthread.so.0
No symbol table info available.
#2  0xb7e550a3 in ?? () from /usr/lib/mozilla-thunderbird/libnspr4.so
No symbol table info available.
#3  0x0827089c in ?? ()
No symbol table info available.
#4  0x08270838 in ?? ()
No symbol table info available.
#5  0xb30ff32c in ?? ()
No symbol table info available.
#6  0xb7e171b5 in pthread_getspecific ()
   from /lib/tls/i686/cmov/libpthread.so.0
No symbol table info available.
#7  0xb7e55ee1 in PR_WaitCondVar ()
   from /usr/lib/mozilla-thunderbird/libnspr4.so
No symbol table info available.
#8  0xb717bd55 in ?? ()
   from /usr/lib/mozilla-thunderbird/components/libnecko.so
No symbol table info available.
#9  0x08270898 in ?? ()
No symbol table info available.
#10 0x0000ea60 in ?? ()
No symbol table info available.
#11 0xb30ff398 in ?? ()
No symbol table info available.
#12 0x08270828 in ?? ()
No symbol table info available.
#13 0x08270828 in ?? ()
No symbol table info available.
#14 0xc8650b6f in ?? ()
No symbol table info available.
#15 0x08270838 in ?? ()
No symbol table info available.
#16 0xb7e64554 in ?? () from /usr/lib/mozilla-thunderbird/libnspr4.so
No symbol table info available.
#17 0x08ef6c30 in ?? ()
No symbol table info available.
#18 0x00000001 in ?? ()
No symbol table info available.
#19 0xb30ff3b8 in ?? ()
No symbol table info available.
#20 0xb7e5bead in ?? () from /usr/lib/mozilla-thunderbird/libnspr4.so
No symbol table info available.
#21 0x08270808 in ?? ()
No symbol table info available.
#22 0x08ef6c30 in ?? ()
No symbol table info available.
#23 0x00000000 in ?? ()
No symbol table info available.

Thread 5 (Thread -1272022128 (LWP 6945)):
#0  0xffffe410 in __kernel_vsyscall ()
No symbol table info available.
#1  0xb7e165c6 in pthread_cond_wait@@GLIBC_2.3.2 ()
   from /lib/tls/i686/cmov/libpthread.so.0
No symbol table info available.
#2  0xb7e55f71 in PR_WaitCondVar ()
   from /usr/lib/mozilla-thunderbird/libnspr4.so
No symbol table info available.
#3  0xb7e55fd7 in PR_Wait () from /usr/lib/mozilla-thunderbird/libnspr4.so
No symbol table info available.
#4  0xb7edeeb1 in PL_WaitForEvent ()
   from /usr/lib/mozilla-thunderbird/libxpcom_core.so
No symbol table info available.
#5  0xb7ee06f9 in ?? () from /usr/lib/mozilla-thunderbird/libxpcom_core.so
No symbol table info available.
#6  0x08e48fc8 in ?? ()
No symbol table info available.
#7  0x08e0d730 in ?? ()
No symbol table info available.
#8  0xb42e6fb8 in ?? ()
No symbol table info available.
#9  0xb7f16904 in ?? () from /usr/lib/mozilla-thunderbird/libxpcom_core.so
No symbol table info available.
#10 0xb7f16904 in ?? () from /usr/lib/mozilla-thunderbird/libxpcom_core.so
No symbol table info available.
#11 0x00000000 in ?? ()
No symbol table info available.

Thread 4 (Thread -1257636976 (LWP 6942)):
#0  0xffffe410 in __kernel_vsyscall ()
No symbol table info available.
#1  0xb7e1684c in pthread_cond_timedwait@@GLIBC_2.3.2 ()
   from /lib/tls/i686/cmov/libpthread.so.0
No symbol table info available.
#2  0xb7e550a3 in ?? () from /usr/lib/mozilla-thunderbird/libnspr4.so
No symbol table info available.
#3  0x0827089c in ?? ()
No symbol table info available.
#4  0x08270838 in ?? ()
No symbol table info available.
#5  0xb509f32c in ?? ()
No symbol table info available.
#6  0xb7e171b5 in pthread_getspecific ()
   from /lib/tls/i686/cmov/libpthread.so.0
No symbol table info available.
#7  0xb7e55ee1 in PR_WaitCondVar ()
   from /usr/lib/mozilla-thunderbird/libnspr4.so
No symbol table info available.
#8  0xb717bd55 in ?? ()
   from /usr/lib/mozilla-thunderbird/components/libnecko.so
No symbol table info available.
#9  0x08270898 in ?? ()
No symbol table info available.
#10 0x0000ea60 in ?? ()
No symbol table info available.
#11 0xb509f398 in ?? ()
No symbol table info available.
#12 0x08270828 in ?? ()
No symbol table info available.
#13 0x08270828 in ?? ()
No symbol table info available.
#14 0xc8642f9f in ?? ()
No symbol table info available.
#15 0x08270838 in ?? ()
No symbol table info available.
#16 0xb7e64554 in ?? () from /usr/lib/mozilla-thunderbird/libnspr4.so
No symbol table info available.
#17 0x08270b28 in ?? ()
No symbol table info available.
#18 0x00000001 in ?? ()
No symbol table info available.
#19 0xb509f3b8 in ?? ()
No symbol table info available.
#20 0xb7e5bead in ?? () from /usr/lib/mozilla-thunderbird/libnspr4.so
No symbol table info available.
#21 0x08270808 in ?? ()
No symbol table info available.
#22 0x08270b28 in ?? ()
No symbol table info available.
#23 0x00000000 in ?? ()
No symbol table info available.

Thread 3 (Thread -1235465328 (LWP 6940)):
#0  0xffffe410 in __kernel_vsyscall ()
No symbol table info available.
#1  0xb7e1684c in pthread_cond_timedwait@@GLIBC_2.3.2 ()
   from /lib/tls/i686/cmov/libpthread.so.0
No symbol table info available.
#2  0xb7e550a3 in ?? () from /usr/lib/mozilla-thunderbird/libnspr4.so
No symbol table info available.
#3  0x0808f854 in ?? ()
No symbol table info available.
#4  0x0808fa18 in ?? ()
No symbol table info available.
#5  0xb65c430c in ?? ()
No symbol table info available.
#6  0xb7e171b5 in pthread_getspecific ()
   from /lib/tls/i686/cmov/libpthread.so.0
No symbol table info available.
#7  0xb7e55ee1 in PR_WaitCondVar ()
   from /usr/lib/mozilla-thunderbird/libnspr4.so
No symbol table info available.
#8  0xb7ee50f6 in ?? () from /usr/lib/mozilla-thunderbird/libxpcom_core.so
No symbol table info available.
#9  0x0808f850 in ?? ()
No symbol table info available.
#10 0x000001e7 in ?? ()
No symbol table info available.
#11 0xb65c4378 in ?? ()
No symbol table info available.
#12 0xb7ee274d in ?? () from /usr/lib/mozilla-thunderbird/libxpcom_core.so
No symbol table info available.
#13 0x00000001 in ?? ()
No symbol table info available.
#14 0x08093f68 in ?? ()
No symbol table info available.
#15 0x0808fa18 in ?? ()
No symbol table info available.
#16 0xb7f16904 in ?? () from /usr/lib/mozilla-thunderbird/libxpcom_core.so
No symbol table info available.
#17 0x081dbe40 in ?? ()
No symbol table info available.
#18 0x081dbe4c in ?? ()
No symbol table info available.
#19 0xb65c4398 in ?? ()
No symbol table info available.
#20 0xb7ee2dfb in ?? () from /usr/lib/mozilla-thunderbird/libxpcom_core.so
No symbol table info available.
#21 0x08093f40 in ?? ()
No symbol table info available.
#22 0x00000000 in ?? ()
No symbol table info available.

Thread 2 (Thread -1223496816 (LWP 6939)):
#0  0xffffe410 in __kernel_vsyscall ()
No symbol table info available.
#1  0xb7583893 in poll () from /lib/tls/i686/cmov/libc.so.6
No symbol table info available.
#2  0xb7e57c39 in PR_Poll () from /usr/lib/mozilla-thunderbird/libnspr4.so
No symbol table info available.
#3  0xb71a017c in ?? ()
   from /usr/lib/mozilla-thunderbird/components/libnecko.so
No symbol table info available.
#4  0x080ecdd0 in ?? ()
No symbol table info available.
#5  0x00000002 in ?? ()
No symbol table info available.
#6  0x03e7fc18 in ?? ()
No symbol table info available.
#7  0xb719fdae in ?? ()
   from /usr/lib/mozilla-thunderbird/components/libnecko.so
No symbol table info available.
#8  0x080ec8e8 in ?? ()
No symbol table info available.
#9  0x080ecdd0 in ?? ()
No symbol table info available.
#10 0x00000002 in ?? ()
No symbol table info available.
#11 0xb72149b8 in ?? ()
   from /usr/lib/mozilla-thunderbird/components/libnecko.so
No symbol table info available.
#12 0xffffffff in ?? ()
No symbol table info available.
#13 0xffffffff in ?? ()
No symbol table info available.
#14 0xb712e378 in ?? ()
No symbol table info available.
#15 0xb71a0965 in ?? ()
   from /usr/lib/mozilla-thunderbird/components/libnecko.so
No symbol table info available.
#16 0x080ec8e8 in ?? ()
No symbol table info available.
#17 0xb712e368 in ?? ()
No symbol table info available.
#18 0x00000001 in ?? ()
No symbol table info available.
#19 0xb7e4621f in PR_SetThreadPrivate ()
   from /usr/lib/mozilla-thunderbird/libnspr4.so
No symbol table info available.
Backtrace stopped: previous frame inner to this frame (corrupt stack?)

Thread 1 (Thread -1220781296 (LWP 6936)):
#0  0xb54e654d in ?? ()
   from /usr/lib/mozilla-thunderbird/components/libgklayout.so
No symbol table info available.
#1  0x0903ef10 in ?? ()
No symbol table info available.
#2  0xbf9b4a9c in ?? ()
No symbol table info available.
#3  0x0903ef10 in ?? ()
No symbol table info available.
#4  0x00000001 in ?? ()
No symbol table info available.
#5  0xbf9b4ae8 in ?? ()
No symbol table info available.
#6  0x00000000 in ?? ()
No symbol table info available.
(gdb) quit
The program is running.  Exit anyway? (y or n) y
jeff@jeff-laptop:~$ 
[/code]

It seems I don't have all the debugging symbols installed but wich package do I have to install??