CLI crashes with --rename-subs and UPPERCASE video extension

- Current Version: 2.0.14
- OS: Ubuntu 11.04

When using the cli version of subdownloader
+ with the option --rename-subs
+ and the target video extesion is in uppercase like .AVI (instead of .avi), I get the following:

$ subdownloader --cli --lang=eng --video=/home/ricky/movietitle.AVI --rename-subs
[...]
{'4153519': <modules.subtitlefile.SubtitleFile object at 0xf87990>, '4061860': <modules.subtitlefile.SubtitleFile object at 0xf87890>}
{'4153519': <modules.subtitlefile.SubtitleFile object at 0xf87990>, '4061860': <modules.subtitlefile.SubtitleFile object at 0xf87890>}
{'4153519': <modules.subtitlefile.SubtitleFile object at 0xf87990>, '4061860': <modules.subtitlefile.SubtitleFile object at 0xf87890>}
{'4153519': <modules.subtitlefile.SubtitleFile object at 0xf87990>, '4061860': <modules.subtitlefile.SubtitleFile object at 0xf87890>}
{'4153519': <modules.subtitlefile.SubtitleFile object at 0xf87990>, '4061860': <modules.subtitlefile.SubtitleFile object at 0xf87890>}
{'4153519': <modules.subtitlefile.SubtitleFile object at 0xf87990>, '4061860': <modules.subtitlefile.SubtitleFile object at 0xf87890>}
{'4153519': <modules.subtitlefile.SubtitleFile object at 0xf87990>, '4061860': <modules.subtitlefile.SubtitleFile object at 0xf87890>}
Traceback (most recent call last):
  File "/usr/bin/subdownloader", line 79, in <module>
    cli.start_session()
  File "/usr/share/subdownloader/cli/main.py", line 107, in start_session
    self.handle_operation(self.options.operation)
  File "/usr/share/subdownloader/cli/main.py", line 156, in handle_operation
    self.DownloadSubtitles(_filter.subtitles_to_download())
  File "/usr/share/subdownloader/modules/SDService.py", line 371, in DownloadSubtitles
    return DownloadSubtitles(subtitles)
  File "/usr/share/subdownloader/modules/SDService.py", line 70, in __call__
    raise e
IOError: [Errno 21] Is a directory: '/home/ricky/'