A little more detail...
Do you hear a welcoming fanfare when you boot 11.2, can you play a CD with Amarok, have you opened a terminal and used the command "alsamixer" to check the settings for your sound?
How did you install VLC, did you use this installer?
You could also install MPlayer, using it as alternative to test your sound system. There is a simple front-end, SMPlayer, that makes MPlayer easy to use.