When increase volume within movie playing in VLC, it alters the whole computer's volume!

some reason, VLC’s volume control is controlling the entire OS’s volume. If I mute the video, it mutes everything, not just the video. And if I change the volume level, it changes the entire OS’s volume. What could be causing this and how do I fix it?

VLC INFO

VLC media player 2.0.1 Twoflower (revision 2.0.1-0-gf432547)
VLC version 2.0.1 Twoflower (2.0.1-0-gf432547)
Compiled by abuild on messiah (May 22 2012 07:39:35)
Compiler: gcc version 4.6.2 (SUSE Linux)