So it confirms there is something is wrong with how the books.db file is getting created by the T1. I'd call it a Sony bug, but they might disagree.
The work around without a fix is to add a book onto the SD card manually before using Calibre to get the T1 to "fix" the books.db itself. Calibre will continue to work fine as long as you don't delete books.db off the card from that point on.
The long-term work around for the bug is have Calibre set the starting id # in books.db if it is an invalid value. Calibre shouldn't have to do this, but developers don't always build their devices in a sane way.
I just have one last question: What firmware do you have on your T1?