When I first installed mumble I did have a ton of issues with the client crashing on start up with error code 2203.
After some Google searching and reading up and down a few topics describing the problem, and multiple solutions about running a "clean" start up of the system and so on and so forth, I found a solution that so far seems to work for me.
I uninstalled the client and re-downloaded a new setup file and then found the folder the file was contained in and checked it to "run as administrator" in its properties (right click).
Then followed the installation wizard while keeping track of your guide on, which by the way is very helpful.
After completing installation of the client, "yeah baby, one step closer", DOOOONGG!! enormous windows error sound.
Now the client crashed for no obvious reason and no error code popped up, so I went on and found the folder where the executable was and checked this one as well to "run as administrator". -nothing!
Last thing I knew of to play around with was the compatible settings and this is where I seem to finally have found the jackpot.
Changing this to "run in Win XP SP3 compatible mode" and starting the client finally opened mumble for me.

yey ....
but now I have a question for YOU
DAMDAMDAMDAAAAMMMM.. PASSWORD
I honestly have no idea how I brought my self to believe I could just log into it without any PW.
So I'm from EU and playing wow on an EU client and I'm not part of any CTR guild in game, as I found out after some research that this is where you keep your PW safe.
As only a forum user/member,and a fairly new one, is there any way for me to join you guys on mumble?