There was an error in backing up my BB PlayBook

Hey guys! I owned a BlackBerry PlayBook with OS 1.0.7.3312. I connected it with my Windows 7 computer.
When I tried to make a full backup of my PlayBook, I got this error:

BlackBerry Desktop Software
There was an error backing up.
There could have been a problem with the device or connection during the backup. Verify that the device is turned on and connected.
OK
I cannot back-up the Application Data, but I already back-up the Settings of my PlayBook. When trying to backup the two at the same time, the error above keeps showing. Any thoughts about this please let me know.
Thank you.
