Backup Completed with Exceptions: Used Tapes still in Scratch Media

1. I am trying to backup a NAS Device (1.6 TB) to a HP 1/8 Storageworks Tape Library.
2. Tapes in the Slots are HP Ultrium LTO3 RW 800 GB (on a 2:1 compression ratio).
3. Due to the size of the Data being backed up during a FULL Backup (1.6 TB) and errors encountered in the past as a result, I divided 1 FULL Backup Job into 4 Separate Sets of Jobs in order to get a more granular look.
4. Jobs are Labelled Job01, Job02, Job03 and Job04.
5. Each of the 4 Jobs are Mutually Exclusive of one another (no data duplication during backup).
6. I created a Partition containing 4 Slots in the BE Console > Devices [0005...0008]. The partiotion contains Slots from 05 until 08.
7. I created a MEDIA SET named SET01 with the following settings: OPP = 2 weeks, AP = 3 Days.
8. I configured the AP at 3 Days because the Media Set would be writing to the partition containing 4 Slots and some of the Jobs may require that the data be 'spanned' across more than 1 Tape.
9. I erased the 4 Tapes. This automatically allocated them to the Scratch Media Set. I did not manually allocate the Tapes to SET01.
10. The 1st Job started on THU 04:52 PM and the Last Job Started on SAT 12:47 AM (therefore the AP configured in SET01 is OK).
11. Job 01 failed reporting a corrupt data (I am not worried as its only 1 file and the rest of them in the Job look okay).
12. Job 02 through 04 completed with 'exceptions'.
13. Apart from 'snapshot_init_failure' Remote Agent not detected on the NAS Device, there seems to be nothing in all the 3 corresponding XML Log files that indicate what the 'exception' really is.
14. I look under Media Sets. Tapes in the Slots 5 and 6 were moved from Scratch Media Set to SET01. Tapes in the Slots 7 & 8 are still in the Scratch Media Set.
15. Tapes in Slots 5, 7 and 8 are Completely Used. The tape in Slot 6 is partially used.

1. Why are the Tapes in Slot 7 and 8 not in SET01 instead of the Scratch Media Set ?
2. Can I remove the 4 tapes from the Tape Library (Manually) and be able to catalog them in the future for any restores ?
3. Where can i look to find out what the 'exception' is really about ?

Thanks a lot !