Can't create issue and other problem

Hi,
I upgraded from d5 to d6, and unfortunately I have many problems!
I'm going to explain all:
1. I created a new issue, number 20, and it seems to be ok, but when I write an article and select the new issue, I receive an error message saying that no issue is selected.
Also, if I try to create another issue, number 21, I receive this error:
user warning: Duplicate entry '0' for key 1 query: INSERT INTO ejournal_issues (jid, year, volume, number, custom_identification, cover_page_nid, date_published, status, issue_order, description) VALUES ('2', '2009', '9', '21', '', '', '1259654400', '2', '0', 'numero 21') in /var/www/vhosts/spazioausili.net/httpdocs/modules/ejournal/ejournal.module on line 2205.

So, I deleted the number 20, I re-create it, and all is the same, I can't insert article in that issue.
This is made by the superuser.

2. In the permissions configurations, I have two ejournals permissions, is it right?
The voices are:

ejournal administrator
ejournal chief editor
ejournal editor
ejournal others
ejournal proofreader
ejournal reviewer
ejournal staff
ejournal-2 author
ejournal-2 chief editor
ejournal-2 editor
ejournal-2 others
ejournal-2 proofreader
ejournal-2 reviewer