Hi Russ,
First of all, you said that you have LTO-6 tapes. So, I recomend you specify it in your Device name definition, that will avoid some confusion in the future:
Device {
Name = ML6000-LTO6-0
...
}
A second question is: don't you have barcodes? Are you sure you're going to work without barcode labels? If you're not going to work with barcodes, you should use the "label" command for labeling the tapes (before you should guarantee they are ready for labeling with mt -f /dev/st0 rewind and weof). The add command, as it tells you when you run it, doesn't labeled your volumes and you need this.
So, use the "label" or "label barcodes" commands, they will label your volumes and records them corretly in the bacula catalog (MediaId, name, slot, inchanger flag, etc.)
Regards,
Ana