Trouble transfering books to my Sony PRS-T1

Hi

I can't seem to connect and transfer books from Calibre to my Sony PRS-T1, this is the error report:

calibre, version 0.8.58
ERROR: Error: Error communicating with device

PRIMARY KEY must be unique

Traceback (most recent call last):
File "site-packages\calibre\gui2\device.py", line 82, in run
File "site-packages\calibre\gui2\device.py", line 340, in _books
File "site-packages\calibre\devices\prst1\driver.py", line 162, in books
File "site-packages\calibre\devices\usbms\driver.py", line 244, in books
File "site-packages\calibre\devices\prst1\driver.py", line 243, in sync_booklists
File "site-packages\calibre\devices\prst1\driver.py", line 273, in update_device_database
File "site-packages\calibre\devices\prst1\driver.py", line 437, in update_device_books
File "site-packages\calibre\devices\prst1\driver.py", line 399, in read_device_books
IntegrityError: PRIMARY KEY must be unique


Can you help point me in the right direction please?

Much appreciated.