Here is what is causing the dpkg error during the upgrade:

Paramétrage de gforge-common (4.6.99+svn6347-1) ...^M
Calculating defaults^M
Reading defaults from /etc/gforge/gforge.conf^M
[: 104: ==: unexpected operator^M
Creating /etc/gforge/gforge.conf^M
[: 107: ==: unexpected operator^M
[: 107: ==: unexpected operator^M
[: 107: ==: unexpected operator^M
SSL Enabled^M
Creating /etc/gforge/httpd.conf^M
Creating /etc/gforge/httpd.secrets^M
Creating /etc/gforge/local.inc^M
Creating other includes^M
^M
Paramétrage de postgresql-common (87) ...^M
Installation de la nouvelle version du fichier de configuration /etc/postgresql-common/autovacuum.conf ...^M
Warning: The following devices contain databases and have write^M
caching enabled: /dev/hda^M
This could destroy the integrity of your databases in the event of power^M
failure. Consider disabling the write cache with "hdparm -W 0 <device>".^M
^M
Paramétrage de postgresql-8.2 (8.2.7-1) ...^M
Creating new cluster (configuration: /etc/postgresql/8.2/main, data: /var/lib/postgresql/8.2/main)...^M
Moving configuration file /var/lib/postgresql/8.2/main/postgresql.conf to /etc/postgresql/8.2/main...^M
Moving configuration file /var/lib/postgresql/8.2/main/pg_hba.conf to /etc/postgresql/8.2/main...^M
Moving configuration file /var/lib/postgresql/8.2/main/pg_ident.conf to /etc/postgresql/8.2/main...^M
Configuring postgresql.conf to use port 5433...^M
 * Starting PostgreSQL 8.2 database server^M
   ...done.^M
^M
Paramétrage de gforge-db-postgresql (4.6.99+svn6347-1) ...^M
Installation de la nouvelle version du fichier de configuration /etc/cron.d/gforge-db-postgresql ...^M
Calculating defaults^M
Reading defaults from /etc/gforge/gforge.conf^M
[: 104: ==: unexpected operator^M
Creating /etc/gforge/gforge.conf^M
[: 107: ==: unexpected operator^M
[: 107: ==: unexpected operator^M
[: 107: ==: unexpected operator^M
SSL Enabled^M
Creating /etc/gforge/httpd.conf^M
Creating /etc/gforge/httpd.secrets^M
Creating /etc/gforge/local.inc^M
Creating other includes^M
Replacing config file /etc/postgresql/7.4/main/pg_hba.conf with new version^M
 * Reloading PostgreSQL 7.4 database server^M
   ...done.^M
Procedural language on gforge already enabled^M
You'll see some debugging info during this installation.^M
Do not worry unless told otherwise.^M
Upgrading with 20050812.sql^M
Updating debian_meta_data table.^M
Committing.^M
Upgrading with 20050822.sql^M
Updating debian_meta_data table.^M
Committing.^M
Upgrading with 20050823.sql^M
Updating debian_meta_data table.^M
Committing.^M
Upgrading with 20050824.sql^M
Updating debian_meta_data table.^M
Committing.^M
Upgrading with 20050831.sql^M
Updating debian_meta_data table.^M
Committing.^M
Upgrading with 20060113.sql^M
Updating debian_meta_data table.^M
Committing.^M
Upgrading with 20060214.sql^M
Updating debian_meta_data table.^M
Committing.^M
Upgrading with 20060216-nocommit.sql^M
Updating debian_meta_data table.^M
Committing.^M
Fixing past mistakes in role naming^M
Updating debian_meta_data table.^M
Committing.^M
Upgrading with 20051103_transiciel_motscle_document.sql^M
Updating debian_meta_data table.^M
Committing.^M
Upgrading with 20070924-forum-perm.sql^M
DBD::Pg::st execute failed: ERREUR:  impossible de convertir le type character varying en integer^M
Transaction aborted because DBD::Pg::st execute failed: ERREUR:  impossible de convertir le type character varying en integer^M
Transaction aborted because DBD::Pg::st execute failed: ERREUR:  impossible de convertir le type character varying en integer^M
Last SQL query was:^M
SELECT value FROM debian_meta_data WHERE key = 'db-version'^M
(end of query)^M
Your database schema is at version 4.6-1^M
Please report this bug on the Debian bug-tracking system.^M
Please include the previous messages as well to help debugging.^M
You should not worry too much about this,^M
your DB is still in a consistent state and should be usable.^M
dpkg : erreur de traitement de gforge-db-postgresql (--configure) :^M
 le sous-processus post-installation script a retourné une erreur de sortie d'état 1^M