Seems at first sight a hardware problem but perhaps is codec-related!
Perhaps try an audio/video transmitter/receiver combination (like I'm using) instead of a rather long cable?
Another idea is that you're using an audio codec which is not entirely up to his task. Do you happen to know which one you have? You may check (with movie playing) through rightclick > Options > Filters > advanced.
(If you're looking in Windows configuration: oddly the codecs installed are shown under Window's hardware of sound/multimedia)
Another thing you could perhaps try is to set "Process priority" of BSPlayer a bit higher: rightclick > Options > Preferences > General
(Process priority can be set there just north-east of [Close] button)