UnicodeDecodeError when using the "sound" component

My guess here is that your sound device has a unicode character in its name on the CZ locale computer and this is causing an error as the log file is written (because it refers to the audio device being used)
@hsogo12600 made a fix to this issue here:
https://github.com/psychopy/psychopy/pull/1403/files

so it might be that you can fetch new copies of

These will be included in the next release.
Jon