[Andrew WCY]

Not sure if this helps, but you could try doing the following:

1. Playing on the old FFR client (http://www.flashflashrevolution.com/....8.Release.zip) might solve this problem.
2. Try updating or downgrading your audio drivers. In the Start Menu, open 'Device Manager'. Then, open the 'Sound, video and game controllers' list, right click your audio driver (e.g. 'Conexant SmartAudio HD') and click 'Properties'. Click the 'Driver' tab, and click either 'Update Driver' or 'Roll Back Driver'.