upgrade from Squeeze to Wheezy

[Pierre Frenkiel <pierre.frenkiel@gmail.com>]

hi,
today, I tried to upgrade from squeeze to wheezzy:
- in source.list, I only left:
    deb http://ftp.fr.debian.org/debian/ wheezy main contrib non-free

- then, apt-get update ; apt-get upgrade
  up to now, no problem, a lot of packages were upgraded
- but after reboot,running "apt-get dist-upgrade" gives:

   Calculating upgrade... Failed
   The following packages have unmet dependencies:
    odbcinst1debian2 : Breaks: libmyodbc (< 5.1.6-2) but 5.1.6-1 is to be installed
          Breaks: odbc-postgresql (< 1:09.00.0310-1.1) but 1:08.03.0200-1.2 is to be installed
          Breaks: tdsodbc (< 0.82-8) but 0.82-7 is to be installed


"lsb-release -r" still gives "squeeze", and and I'm left with about
1700 packages "not upgraded"

Is there a way to  fix this dependency problem? I found nothing
useful (at least for me) via Google, or debian forums.

best regards,
--
Pierre Frenkiel