I wonder if it isn't a matter of a missing codec, which your PC is trying to pick up from the internet.
Can you play the same movie-file in another player? (Try e.g. Windows Media Player) and what is the result?
(If WMP causes the same action, I would suggest to allow WMP to connect to the internet so that the (upgrade of the) codec can be downloaded and installed (if it can be found at MS); once the codec is downloaded and installed, it is - of course - not only available to WMP, but (i.a.) also to BSPlayer).
If that doesn't do the trick, you'll first have to find out what codec is used by the movie in question. Applications like GSpot or AviCodec can assist you at that:
http://www.headbands.com/gspot/
respectively
http://avicodec.duby.info/ 
Another possibility is that you perhaps need to do a "Windows Update".
(If you uncheck "Auto play" in "General"-tab of "Preferences" and then load (from BSPlayer's control panel) a moviefile without a subtitlefile, what happens if you press "Play"-button?)
(You'll have to temporarily rename subtitlefile first if it has the same name as the videofile and/or select "Don't show subtitles" in the Subtitle-section of "Preferences")