The full error is: "Unable to find matching CELT codecs with other clients. You will not be able to talk to all users." It appears that the version of CELT in Ubuntu's repository is outdated, and compiling it from source does not seem to be effective. Does anyone know how to solve this? Even a .deb of the 0.11.1 codecs would be great. Thanks for your help. I'm running Ubuntu 11.10.