We have found the following problem restoring a backup course:

S'estan creant els grups ("Creating groups...")

ORA-00918: column ambiguously defined

SELECT * FROM mlgroups g, mlgroups_courses_groups gcg WHERE gcg.courseid = 181 AND g.id = gcg.groupid AND g.name = 'Group B' AND dbms_lob.substr(description, 32,1) = dbms_lob.substr('Description of the group', 32,1)

    * line 677 of lib/dmllib.php: call to debugging()
    * line 474 of lib/dmllib.php: call to get_recordset_sql()
    * line 2234 of backup/restorelib.php: call to get_record_sql()
    * line 6153 of backup/restorelib.php: call to restore_create_groups()
    * line 47 of backup/restore_execute.html: call to restore_execute()
    * line 162 of backup/restore.php: call to include_once()

Otherwise, when we execute this SQL Query directly in our database it works fine.