Got a similar error (with the driver you added to the #8283 ticket)
Code:
calibre, version 0.7.43
ERROR: Unhandled exception: <b>AttributeError</b>:'MessageBox' object has no attribute 'setDetailedText'
Traceback (most recent call last):
File "site-packages\calibre\gui2\__init__.py", line 242, in dispatch
File "site-packages\calibre\gui2\device.py", line 1187, in books_uploaded
File "site-packages\calibre\gui2\device.py", line 692, in device_job_exception
AttributeError: 'MessageBox' object has no attribute 'setDetailedText'
--Mags