Le message retourné est trop long pour être posté ici. J'envoie le début de celui-ci.
J'ai copié le message complet dans un fichier txt mais je ne sais pas comment le poster ici.

C:\Program Files\OpenERP 6.0\PostgreSQL\bin\pg_restore.exe --host localhost --port 5432 --username "openerp" --dbname "essai1" --verbose "C:\coco.backup"
pg_restore: connecting to database for restore
pg_restore: creating SCHEMA public
pg_restore: creating COMMENT SCHEMA public
pg_restore: creating TABLE account_account
pg_restore: [archiver (db)] Error while PROCESSING TOC:
pg_restore: [archiver (db)] Error from TOC entry 2619; 1259 22481 TABLE account_account openerp
pg_restore: [archiver (db)] could not execute query: ERROR:  relation "account_account" already exists
    Command was:
CREATE TABLE account_account (
    id integer NOT NULL,
    parent_left integer,
    parent_right integer,
    create_uid i...
pg_restore: creating COMMENT TABLE account_account
pg_restore: creating COMMENT COLUMN account_account.code
pg_restore: creating COMMENT COLUMN account_account.reconcile
pg_restore: creating COMMENT COLUMN account_account.currency_id
pg_restore: creating COMMENT COLUMN account_account.user_type
pg_restore: creating COMMENT COLUMN account_account.active
pg_restore: creating COMMENT COLUMN account_account.name
pg_restore: creating COMMENT COLUMN account_account.level
pg_restore: creating COMMENT COLUMN account_account.company_id
pg_restore: creating COMMENT COLUMN account_account.shortcut
pg_restore: creating COMMENT COLUMN account_account.note
pg_restore: creating COMMENT COLUMN account_account.parent_id
pg_restore: creating COMMENT COLUMN account_account.currency_mode
pg_restore: creating COMMENT COLUMN account_account.type
pg_restore: creating TABLE account_account_consol_rel
pg_restore: [archiver (db)] Error from TOC entry 2620; 1259 22509 TABLE account_account_consol_rel openerp
pg_restore: [archiver (db)] could not execute query: ERROR:  relation "account_account_consol_rel" already exists
    Command was: CREATE TABLE account_account_consol_rel (
    child_id integer NOT NULL,
    parent_id integer NOT NULL
);
pg_restore: creating COMMENT TABLE account_account_consol_rel
pg_restore: creating TABLE account_account_tax_default_rel
pg_restore: [archiver (db)] Error from TOC entry 2621; 1259 22542 TABLE account_account_tax_default_rel openerp
pg_restore: [archiver (db)] could not execute query: ERROR:  relation "account_account_tax_default_rel" already exists
    Command was: CREATE TABLE account_account_tax_default_rel (
    account_id integer NOT NULL,
    tax_id integer NOT NULL
);
pg_restore: creating COMMENT TABLE account_account_tax_default_rel
pg_restore: creating TABLE account_account_template
pg_restore: [archiver (db)] Error from TOC entry 2654; 1259 23065 TABLE account_account_template openerp
pg_restore: [archiver (db)] could not execute query: ERROR:  relation "account_account_template" already exists
    Command was: CREATE TABLE account_account_template (
    id integer NOT NULL,
    create_uid integer,
    create_date timestamp without t...
pg_restore: creating COMMENT TABLE account_account_template
pg_restore: creating COMMENT COLUMN account_account_template.currency_id
pg_restore: creating COMMENT COLUMN account_account_template.code
pg_restore: creating COMMENT COLUMN account_account_template.name
pg_restore: creating COMMENT COLUMN account_account_template.user_type
pg_restore: creating COMMENT COLUMN account_account_template.shortcut
pg_restore: creating COMMENT COLUMN account_account_template.note
pg_restore: creating COMMENT COLUMN account_account_template.parent_id
pg_restore: creating COMMENT COLUMN account_account_template.nocreate
pg_restore: creating COMMENT COLUMN account_account_template.reconcile
pg_restore: creating COMMENT COLUMN account_account_template.type
pg_restore: creating TABLE account_account_template_tax_rel
pg_restore: [archiver (db)] Error from TOC entry 2655; 1259 23101 TABLE account_account_template_tax_rel openerp
pg_restore: [archiver (db)] could not execute query: ERROR:  relation "account_account_template_tax_rel" already exists
    Command was: CREATE TABLE account_account_template_tax_rel (
    account_id integer NOT NULL,
    tax_id integer NOT NULL
);
pg_restore: creating COMMENT TABLE account_account_template_tax_rel
pg_restore: creating TABLE account_account_type
pg_restore: [archiver (db)] Error from TOC entry 2615; 1259 22441 TABLE account_account_type openerp
pg_restore: [archiver (db)] could not execute query: ERROR:  relation "account_account_type" already exists
    Command was: CREATE TABLE account_account_type (
    id integer NOT NULL,
    create_uid integer,
    create_date timestamp without time ...
pg_restore: creating COMMENT TABLE account_account_type
pg_restore: creating COMMENT COLUMN account_account_type.note
pg_restore: creating COMMENT COLUMN account_account_type.close_method
pg_restore: creating COMMENT COLUMN account_account_type.code
pg_restore: creating COMMENT COLUMN account_account_type.name
pg_restore: creating COMMENT COLUMN account_account_type.report_type
pg_restore: creating COMMENT COLUMN account_account_type.sign
pg_restore: creating TABLE account_account_type_rel
pg_restore: [archiver (db)] Error from TOC entry 2630; 1259 22675 TABLE account_account_type_rel openerp
pg_restore: [archiver (db)] could not execute query: ERROR:  relation "account_account_type_rel" already exists
    Command was: CREATE TABLE account_account_type_rel (
    journal_id integer NOT NULL,
    account_id integer NOT NULL
);
pg_restore: creating COMMENT TABLE account_account_type_rel
pg_restore: creating TABLE account_analytic_account
pg_restore: [archiver (db)] Error from TOC entry 2544; 1259 21353 TABLE account_analytic_account openerp
pg_restore: [archiver (db)] could not execute query: ERROR:  relation "account_analytic_account" already exists
    Command was: CREATE TABLE account_analytic_account (
    id integer NOT NULL,
    create_uid integer,
    create_date timestamp without t...
pg_restore: creating COMMENT TABLE account_analytic_account
pg_restore: creating COMMENT COLUMN account_analytic_account.code
pg_restore: creating COMMENT COLUMN account_analytic_account.description
pg_restore: creating COMMENT COLUMN account_analytic_account.quantity_max
pg_restore: creating COMMENT COLUMN account_analytic_account.contact_id
pg_restore: creating COMMENT COLUMN account_analytic_account.currency_id
pg_restore: creating COMMENT COLUMN account_analytic_account.date
pg_restore: creating COMMENT COLUMN account_analytic_account.partner_id
pg_restore: creating COMMENT COLUMN account_analytic_account.user_id
pg_restore: creating COMMENT COLUMN account_analytic_account.name
pg_restore: creating COMMENT COLUMN account_analytic_account.date_start
pg_restore: creating COMMENT COLUMN account_analytic_account.company_id
pg_restore: creating COMMENT COLUMN account_analytic_account.parent_id
pg_restore: creating COMMENT COLUMN account_analytic_account.state
pg_restore: creating COMMENT COLUMN account_analytic_account.type
pg_restore: creating TABLE account_analytic_journal
pg_restore: [archiver (db)] Error from TOC entry 2667; 1259 23348 TABLE account_analytic_journal openerp
pg_restore: [archiver (db)] could not execute query: ERROR:  relation "account_analytic_journal" already exists
    Command was: CREATE TABLE account_analytic_journal (
    id integer NOT NULL,
    create_uid integer,
    create_date timestamp without t...
pg_restore: creating COMMENT TABLE account_analytic_journal
pg_restore: creating COMMENT COLUMN account_analytic_journal.code
pg_restore: creating COMMENT COLUMN account_analytic_journal.name
pg_restore: creating COMMENT COLUMN account_analytic_journal.active
pg_restore: creating COMMENT COLUMN account_analytic_journal.type
pg_restore: creating COMMENT COLUMN account_analytic_journal.company_id
pg_restore: creating TABLE account_analytic_line
pg_restore: [archiver (db)] Error from TOC entry 2546; 1259 21406 TABLE account_analytic_line openerp
pg_restore: [archiver (db)] could not execute query: ERROR:  relation "account_analytic_line" already exists
    Command was: CREATE TABLE account_analytic_line (
    id integer NOT NULL,
    create_uid integer,
    create_date timestamp without time...