Backup and restore

My courses no longer restore, although it says complete all you get is the resource/activity icon and no link.

With debugging turned up I get loads of...

Creating sections
Duplicate entry '4294967295' for key 1

INSERT INTO mdl_backup_ids ( BACKUP_CODE, TABLE_NAME, OLD_ID, NEW_ID, INFO ) VALUES ( 1191417264, 'course_sections', 152, 2573, 's:0:"";' )

* line 1425 of lib/dmllib.php: call to debugging()
* line 472 of backup/lib.php: call to insert_record()
* line 947 of backup/restorelib.php: call to backup_putid()
* line 5867 of backup/restorelib.php: call to restore_create_sections()
* line 46 of backup/restore_execute.html: call to restore_execute()
* line 160 of backup/restore.php: call to include_once()


Duplicate entry '4294967295' for key 1

INSERT INTO mdl_backup_ids ( BACKUP_CODE, TABLE_NAME, OLD_ID, NEW_ID, INFO ) VALUES ( 1191417264, 'course_modules', 363, 4359, 's:2:"17";' )

* line 1425 of lib/dmllib.php: call to debugging()
* line 472 of backup/lib.php: call to insert_record()
* line 1005 of backup/restorelib.php: call to backup_putid()
* line 5867 of backup/restorelib.php: call to restore_create_sections()
* line 46 of backup/restore_execute.html: call to restore_execute()
* line 160 of backup/restore.php: call to include_once()

I can't quite get my head around what key 1 is, but I can't find any likely entries for the offending value in any field.

Slightly more oddly this site (1.8.2+ from a few weeks ago) has a rather different index profile to my latest cvs 1.8.2+ site, which restores the same courses fine..

Broken course:
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment
mdl_backup_ids 0 PRIMARY 1 id A 0 BTREE
mdl_backup_ids 0 backup_ids_uk 1 backup_code A BTREE
mdl_backup_ids 0 backup_ids_uk 2 table_name A BTREE
mdl_backup_ids 0 backup_ids_uk 3 old_id A 0 BTREE

Good course:
+----------------+------------+---------------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+
| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment |
+----------------+------------+---------------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+
| mdl_backup_ids | 0 | PRIMARY | 1 | id | A | 0 | NULL | NULL | | BTREE | |
| mdl_backup_ids | 0 | mdl_backids_bactabold_uix | 1 | backup_code | A | NULL | NULL | NULL | | BTREE | |
| mdl_backup_ids | 0 | mdl_backids_bactabold_uix | 2 | table_name | A | NULL | NULL | NULL | | BTREE | |
| mdl_backup_ids | 0 | mdl_backids_bactabold_uix | 3 | old_id | A | 0 | NULL | NULL | | BTREE | |
+----------------+------------+---------------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+