Following a lead on irc we tryed something

<meineerde> braoru: that can happen when you have journal entries left for objects which are deleted by hand
<meineerde> braoru: you can search in jour journals table for entries with journalized_type == "Document"  and a journalized_id of a document that isn't there anymore.

But there is no entry of type Document in the database

mysql> select count(*),type from journals group by type;
+----------+-------------------+
| count(*) | type              |
+----------+-------------------+
|     2936 | AttachmentJournal |
|    23654 | IssueJournal      |
+----------+-------------------+
2 rows in set (0.01 sec)

Following meineerde lead I tried to find what (if there is one) id the default document type.

mysql> select * from enumerations;
+----+-------------------------+----------+------------+-------------------+--------+------------+-----------+
| id | name                    | position | is_default | type              | active | project_id | parent_id |
+----+-------------------------+----------+------------+-------------------+--------+------------+-----------+
|  2 | Technical documentation |        1 |          0 | DocumentCategory  |      1 |       NULL |      NULL |
|  3 | Low                     |        1 |          0 | IssuePriority     |      1 |       NULL |      NULL |
|  4 | Normal                  |        2 |          1 | IssuePriority     |      1 |       NULL |      NULL |
|  5 | High                    |        3 |          0 | IssuePriority     |      1 |       NULL |      NULL |
|  8 | Design                  |        1 |          0 | TimeEntryActivity |      1 |       NULL |      NULL |
|  9 | Development             |        2 |          0 | TimeEntryActivity |      1 |       NULL |      NULL |
| 10 | Meeting                 |        3 |          0 | TimeEntryActivity |      1 |       NULL |      NULL |
| 11 | Training                |        4 |          0 | TimeEntryActivity |      1 |       NULL |      NULL |
| 12 | Vacation (vacances)     |        5 |          0 | TimeEntryActivity |      1 |       NULL |      NULL |
| 13 | Disease (malade)        |        6 |          0 | TimeEntryActivity |      1 |       NULL |      NULL |
| 14 | Support                 |        7 |          0 | TimeEntryActivity |      1 |       NULL |      NULL |
| 15 | LSD                     |        8 |          0 | TimeEntryActivity |      1 |       NULL |      NULL |
| 16 | Vacation (vacances)     |        9 |          0 | TimeEntryActivity |      0 |          3 |        12 |
| 17 | Disease (malade)        |       10 |          0 | TimeEntryActivity |      0 |          3 |        13 |
| 18 | Vacation (vacances)     |       11 |          0 | TimeEntryActivity |      0 |          2 |        12 |
| 19 | Disease (malade)        |       12 |          0 | TimeEntryActivity |      0 |          2 |        13 |
| 20 | Vacation (vacances)     |       13 |          0 | TimeEntryActivity |      0 |          4 |        12 |
| 21 | Disease (malade)        |       14 |          0 | TimeEntryActivity |      0 |          4 |        13 |
| 22 | Training                |       15 |          0 | TimeEntryActivity |      1 |          6 |        11 |
| 23 | Vacation (vacances)     |       16 |          0 | TimeEntryActivity |      0 |          6 |        12 |
| 24 | Disease (malade)        |       17 |          0 | TimeEntryActivity |      0 |          6 |        13 |
| 25 | Support                 |       18 |          0 | TimeEntryActivity |      1 |          6 |        14 |
| 26 | LSD                     |       19 |          0 | TimeEntryActivity |      1 |          6 |        15 |
| 27 | Meeting                 |       20 |          0 | TimeEntryActivity |      1 |          6 |        10 |
| 28 | Vacation (vacances)     |       21 |          0 | TimeEntryActivity |      0 |          7 |        12 |
| 29 | Disease (malade)        |       22 |          0 | TimeEntryActivity |      0 |          7 |        13 |
| 30 | Vacation (vacances)     |       23 |          0 | TimeEntryActivity |      0 |          8 |        12 |
| 31 | Disease (malade)        |       24 |          0 | TimeEntryActivity |      0 |          8 |        13 |
| 33 | Meeting minutes         |        2 |          0 | DocumentCategory  |      1 |       NULL |      NULL |
+----+-------------------------+----------+------------+-------------------+--------+------------+-----------+
29 rows in set (0.00 sec)

There is no default type, I set the is_default to 1 for the id 2.

mysql> update enumerations set is_default=1 where id = 2;
Query OK, 1 row affected (0.00 sec)

And try to re-launch the migration script

[root@ecudesp chiliproject]# bundle exec rake db:migrate RAILS_ENV=production
==  BuildInitialJournalsForActsAsJournalized: migrating =======================
-- Building initial journals for Message
   -> 0.0009s
-- Building initial journals for Attachment
   -> 64.6090s
-- Building initial journals for Document
   -> 0.1795s
-- Building initial journals for Changeset
   -> 113.3160s
-- Building initial journals for Issue
rake aborted!
An error has occurred, all later migrations canceled:

can't convert nil into Integer
/var/www/cgi-bin/chiliproject/vendor/plugins/acts_as_journalized/lib/redmine/acts/journalized/creation.rb:102:in `recreate_initial_journal!'
db/migrate//20100714111653_build_initial_journals_for_acts_as_journalized.rb:45:in `block (3 levels) in up'
db/migrate//20100714111653_build_initial_journals_for_acts_as_journalized.rb:41:in `block (2 levels) in up'
db/migrate//20100714111653_build_initial_journals_for_acts_as_journalized.rb:30:in `block in up'
db/migrate//20100714111653_build_initial_journals_for_acts_as_journalized.rb:29:in `each'
db/migrate//20100714111653_build_initial_journals_for_acts_as_journalized.rb:29:in `up'
Tasks: TOP => db:migrate
(See full trace by running task with --trace)
[root@ecudesp chiliproject]# 

Ok for the document but here is another error in the issues migration about type conversion.

Ah, I had the "nil" errors, too. Often these result in deleted users, so going through the history would crash the migration scripts...

Do you have deleted projects, users or comparable resources which are referenced in the journals?