Hi Paka,
as 42IO said, the error message is referring to your open_basedir parameter from your php.ini.
This is the explanation for open_basedir
; open_basedir, if set, limits all file operations to the defined directory
So you can either just put a semicolon in front of the parameter, or you need to add the correct folder paths, for it to work correctly.
Please make sure to either reload or restart your Apache, after you made changes to your php.ini