Hello.
What Software version do You use exactly? If You don't use the latest Software version, please install it. Then install these drivers (
http://octoplusbox.com/files/drivers...Ver_3.12.3.exe,
https://mega.co.nz/#!OlxHUKzC!j5qLEU..._sS4v0fK02kQUg), disconnect all devices from your PC, re-boot the PC, re-start the phone, turn on USB Debugging Mode and try to repeat the operation again. Post here the result.