[nnanna01]

I was having some trouble with my reader and decided to start from scratch and reformatted my reader. Before I reformatted it I had no problem transferring files from Calibre to my reader. Now when I try to transfer files from Calibre to my reader I get this message : "Error communicating with device"
Can someone please tell me what's wrong?
author

Traceback (most recent call last):
File "site-packages\calibre\gui2\device.py", line 56, in run
File "site-packages\calibre\gui2\device.py", line 233, in _upload_books
File "site-packages\calibre\devices\prs505\driver.py", line 132, in upload_books
File "site-packages\calibre\devices\usbms\device.py", line 811, in create_upload_path
File "site-packages\calibre\library\save_to_disk.py", line 137, in get_components
File "site-packages\calibre\library\save_to_disk.py", line 100, in safe_format
KeyError: u'author'