Q6. Some parts don't work, why?

Three possible reasons:

A. Missing Components
The theme author forgot to include one or more components of a theme when zipping up the theme package.

B. Misnamed Files
The theme author has specified a file name for a component of a theme inside the theme file, that is different from the actual file name of the component. E.g. There is a file called wave1.wav and it is used as the sound when Microsoft Windows start. But inside the theme file it is specified as wav.wav .

C. Different Sound Format
Sounds in some themes are encoded in MPEG Layer 3 format. Therefore you may not hear the sounds. The best is that you check with the theme creator what you would need to install.