Fileinfo/mime_content_type configuration:  OK
Mimetype to file extension mapping:  NOT OK

Please set a valid path to your webserver's mime.types file to the mime_types config option.
If you can't find such a file, download it from svn.apache.org.
 

I copied the mime.types file into the root Roundcube folder, and declared it in the config file for version 1.0.0 like so:

$config['mime_types'] = '/www/wwwroot/roundcubemail-1.0.0/config/mime.types';

That worked for me, the installer says mine is OK.

在Roundcube配置文件roundcubemail-1.0.0/config/config.inc.php中定义mime.types

$config['mime_types'] = '/www/wwwroot/roundcubemail-1.0.0/config/mime.types';