Installation error

Hi, I have a problem with the installation of Meta Slider: it is impossible to install the plugin. I have a WordPress website and I tried to install the plugin many times in more ways:

1. With WordPress directly: there is an error message like:
It is impossible to copy ml-slider/languages/ml-slider-ru_RU.mo
or
ml-slider/assets/sliders/flexslider/jquery.flexslider.min.js
It is very strange because if I open the files with my host, I can find the folder ml-slider.

2. With WordPress, uploading the zip file: not working

3. Through my host server, uploading the zip file: I could upload it but I cannot unzip it. The message is:
Archive: /home/crealexi/public_html/wp-content/plugins/ml-slider.3.6.8.zip
End-of-central-directory signature not found. Either this file is not
a zipfile, or it constitutes one disk of a multi-part archive. In the
latter case the central directory and zipfile comment will be found on
the last disk(s) of this archive.
unzip: cannot find zipfile directory in one of /home/crealexi/public_html/wp-content/plugins/ml-slider.3.6.8.zip or
/home/crealexi/public_html/wp-content/plugins/ml-slider.3.6.8.zip.zip, and cannot find /home/crealexi/public_html/wp-content/plugins/ml-slider.3.6.8.zip.ZIP, period.

4. I thought that the problem was that the web hosting account space was almost full, but I upgraded it so now I have a plenty of space.

Could you help me?