after version05.11 , -b switch leads to file being used error

i have figured it out.
the -b switch codeline causes error.it creates the file but cannot start download somehow.dunno why..if i dont use -b, it downloads well as flv

for the latest version tip->
C:\Users\baris\Desktop\test>youtube-dl.py -b "http://www.youtube.com/watch?v=6fM
A8pgWxlk"
[youtube] Setting language
WARNING: unable to set language: <urlopen error [Errno 10054] An existing connec
tion was forcibly closed by the remote host>
[youtube] 6fMA8pgWxlk: Downloading video webpage
[youtube] 6fMA8pgWxlk: Extracting video information
[youtube] 6fMA8pgWxlk: URL: http://www.youtube.com/get_video?video_id=6fMA8pgWxl\\
k&t=vjVQa1PpcFNuIahqeVtAFJi94iqTRJaWaf_JkuFfm1Y=&el=detailpage&ps=&fmt=22
[download] Destination: 6fMA8pgWxlk.mp4
Traceback (most recent call last):
File "C:\Users\baris\Commands\youtube-dl.py", line 1123, in <module>
retcode = fd.download(all_urls)
File "C:\Users\baris\Commands\youtube-dl.py", line 317, in download
ie.extract(url)
File "C:\Users\baris\Commands\youtube-dl.py", line 416, in extract
return self._real_extract(url)
File "C:\Users\baris\Commands\youtube-dl.py", line 644, in _real_extract
'ext': video_extension.decode('utf-8',
File "C:\Users\baris\Commands\youtube-dl.py", line 289, in process_info
os.remove(filename)
WindowsError: [Error 32] The process cannot access the file because it is being
used by another process: u'6fMA8pgWxlk.mp4'

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