That message is coming from ALSA itself, not Steam, so something in your system configuration appears off. I did a quick web search and there are multiple threads on this error message but it didn't seem like there was a single solution.
I've also seen this since last update.
ALSA lib conf.c:3314:(snd_config_hooks_call) Cannot open shared library libasound_module_conf_pulse.so
ALSA lib control.c:951:(snd_ctl_open_noupdate) Invalid CTL hw:0
I only started getting it with the most recent update.
if you are using Debian/Ubuntu and running on a 64-bit system (amd64) do you have the 32-bit asound2's plugins installed (libasound2-plugins:i386)?
sudo apt-get install libasound2-plugins:i386
@alama: Good point, I didn't have, seems it fixed the problem. Thanks for the idea.
That seemed to fix it.
Can't believe I missed that.
Nothing extracted yet.
System Info: https://gist.github.com/45ed161ede54ebc30909
The above is called when I open the Steam client (not doing anything at all besides that). This may occur, as far as I can tell, because the client is looking for it in the wrong directory.