• I don't see anything in the code where system databases are excluded. I would suggest running this query on the instances where the system databases are not reporting as successfully backed up:

    SELECT @@servername, backup_set_id, database_name, backup_start_date, backup_finish_date, user_name,type

    FROM backupset

    WHERE type IN ('D','I')

    AND backup_start_date > 2009-10-20

    AND database_name in ('master','model','msdb')

    One thought, I've seen servers where the @@servername does not return to the correct server name. This can cause problems for the report. This happpens if the server was renamed or master database restored from another server. You can fix this by using sp_dropserver and sp_addserver 'local', see Books Online.