Send to Device doesn't show

[kel]

I use Calibre with a Samsung Galaxy 3 tablet. I've download books on it before with no problems. The past two weeks I don't get a Send to Device when I connect my tablet. I ran a debug and got the following. Please help! I use Calibre 2.20 and Windows.

calibre Debug log
calibre 2.20 isfrozen: True is64bit: False
Windows-7-6.1.7601-SP1 Windows ('32bit', 'WindowsPE')
32bit process running on 64bit windows
('Windows', '7', '6.1.7601')
Python 2.7.9
Windows: ('7', '6.1.7601', 'SP1', 'Multiprocessor Free')
Starting up...
Failed to load cached store: smashwords
Traceback (most recent call last):
  File "site-packages\calibre\gui2\store\loader.py", line 87, in load_cache
  File "site-packages\calibre\gui2\store\loader.py", line 174, in load_object
  File "<string>", line 17, in <module>
ImportError: No module named PyQt4.Qt
Failed to load cached store: wolnelektury
Traceback (most recent call last):
  File "site-packages\calibre\gui2\store\loader.py", line 87, in load_cache
  File "site-packages\calibre\gui2\store\loader.py", line 174, in load_object
  File "<string>", line 15, in <module>
ImportError: No module named PyQt4.Qt
Loaded cached store plugin for: Amazon Kindle at version: 8
Failed to load cached store: whsmith_uk
Traceback (most recent call last):
  File "site-packages\calibre\gui2\store\loader.py", line 87, in load_cache
  File "site-packages\calibre\gui2\store\loader.py", line 174, in load_object
  File "<string>", line 15, in <module>
ImportError: No module named PyQt4.Qt
Failed to load cached store: publio
Traceback (most recent call last):
  File "site-packages\calibre\gui2\store\loader.py", line 87, in load_cache
  File "site-packages\calibre\gui2\store\loader.py", line 174, in load_object
  File "<string>", line 15, in <module>
ImportError: No module named PyQt4.Qt
Failed to load cached store: amazon_ca
Traceback (most recent call last):
  File "site-packages\calibre\gui2\store\loader.py", line 87, in load_cache
  File "site-packages\calibre\gui2\store\loader.py", line 174, in load_object
  File "<string>", line 14, in <module>
ImportError: No module named PyQt4.Qt
Failed to load cached store: kobo
Traceback (most recent call last):
  File "site-packages\calibre\gui2\store\loader.py", line 87, in load_cache
  File "site-packages\calibre\gui2\store\loader.py", line 174, in load_object
  File "<string>", line 16, in <module>
ImportError: No module named PyQt4.Qt
Failed to load cached store: mills_boon_uk
Traceback (most recent call last):
  File "site-packages\calibre\gui2\store\loader.py", line 87, in load_cache
  File "site-packages\calibre\gui2\store\loader.py", line 174, in load_object
  File "<string>", line 15, in <module>
ImportError: No module named PyQt4.Qt
Failed to load cached store: legimi
Traceback (most recent call last):
  File "site-packages\calibre\gui2\store\loader.py", line 87, in load_cache
  File "site-packages\calibre\gui2\store\loader.py", line 174, in load_object
  File "<string>", line 17, in <module>
ImportError: No module named PyQt4.Qt
Error during device detection for <calibre.devices.mtp.driver.MTP_DEVICE object at 0x03237FF0>:
Traceback (most recent call last):
  File "site-packages\calibre\gui2\device.py", line 285, in detect_device
  File "site-packages\calibre\devices\mtp\windows\driver.py", line 35, in check_thread
  File "site-packages\calibre\devices\mtp\windows\driver.py", line 108, in detect_managed_devices
WPDError: Failed to get objects from device: hr=2147946706 facility=7 error_code=4306 description: The library, drive, or media pool is empty.

Started up in 5.64 seconds with 716 books
Error during device detection for <calibre.devices.mtp.driver.MTP_DEVICE object at 0x03237FF0>:
Traceback (most recent call last):
  File "site-packages\calibre\gui2\device.py", line 285, in detect_device
  File "site-packages\calibre\devices\mtp\windows\driver.py", line 35, in check_thread
  File "site-packages\calibre\devices\mtp\windows\driver.py", line 108, in detect_managed_devices
WPDError: Failed to get objects from device: hr=2147946706 facility=7 error_code=4306 description: The library, drive, or media pool is empty.

[Kovid Goyal (kovid)]

That is an error communicating with the device. Usually, this kind of error can be fixed
by rebooting both the device and the computer. If that does not work, you can try resetting
the device, or you can use one of the wireless communication methods described here:
http://manual.calibre-ebook.com/faq.html#how-do-i-use-calibre-with-my-android-phone-tablet-or-kindle-fire-hd

 status invalid