That is not a critical error. It is just a warning that there is a call to gtk_disable_setlocale() that will be ignored. That happens for me too, but not a problem.
A similar problem was reported on Ubuntu, which was solved here: Audacity wont run [SOLVED] - #7 by steve
Note that on first attempt, danzi did not follow the instructions, so the fix did not work first time. On second attempt, he followed the instructions and Audacity was then working again.