For anyone having a problem with Mumble 15th Jan 2012 onwards, please read the following:-
SOURCE:
http://blog.mumble.info/important-update-to-mumble-1-2-3a/IMPORTANT: Update to Mumble 1.2.3a
Posted on January 15, 2012 by .D0T
Due to an expiring certificate no Mumble 1.2.2 or newer released before today (15.01.2012) will work on the Windows Platform after 15 January 2012 11:36:47 GMT. If such an outdated Mumble is launched after that date the error message “A referral was returned by the server” will be displayed by Windows and Mumble will not start.
You can download a fixed Mumble.exe for the 1.2.3 stable from:
http://sourceforge.net/projects/mumble/files/Mumble/1.2.3a/mumble-1.2.3-resigned-binary.zip/download We are sorry for the inconvenience this may cause. We will follow up with a more detailed explanation later.
Regards,
The Mumble team
Just download and unzip this file, it contains the application mumble.exe replace the one in your mumble folder with this one and run as normal.