I used module-assistant to update alsa and it has seemed to changed something but not the reason I tried to upgrade...I want to get sounds from two or more apps to play together, instead of queued??

I didn't fix that but now I have synaptic telling me I have a broken package and I need to install alsa-utils...I try but get

Unpacking alsa-utils (from .../alsa-utils_1.0.8-4_i386.deb) ...
dpkg: error processing /var/cache/apt/archives/alsa-utils_1.0.8-4_i386.deb (--unpack):
trying to overwrite `/usr/bin/alsamixer', which is also in package knx-alsa
dpkg-deb: subprocess paste killed by signal (Broken pipe)
Errors were encountered while processing:
/var/cache/apt/archives/alsa-utils_1.0.8-4_i386.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)

....so until I can fix this error I can't fix the broken package error?

My sound system is working ok except I can't get say desktop sound and audacity or xmms playing together??

can you help with any of these problems??