I will try to be as specific as possible with my problem:

I've installed the Debian Testing distro (Sarge) and am running it under KDE. The problem that I'm having with the sound is very odd. The sound for system files works fine (all the little alerts like the "You just opened a new window" sound), but when I run some other applications the sound doesn't work at all. The main things that I'm noticing the problem with is when I play flash videos with firefox and the firefox flash plugin, and the vlc player that I installed using the apt-get install vlc command. In my feeble attempts to fix the problem in system configure playing a test sound worked but playing a test midi did not. I hope I've given enough information.

sounds like sounds work for root, but not any users. try adding users to the audio group

#adduser "user" audio

or something like that, forget, google it.

Running the reconfigure line(#dpkg-reconfigure xserver-xfree86) and simply going through the steps fixed my problem, It was probably because I also just updated my distro though and then reconfiged it.