You should be able to, but it would depend on the host. You just need to specify the base directory for the files, and that directory should be kept outside of the web root directory so that it can not be accessed directly, but only by the download.php script. Line looks like the following:
define('BASE_DIR','E:/inetpub/securedocs');
For the log file, you just need to make sure LOG_DOWNLOADS is set to true and you define a path for the log file. Also make sure you give permissions to the log file for your Web server to be able to write to it. The lines look like the following:
// log downloads? true/false
define('LOG_DOWNLOADS',true);
// log file name
define('LOG_FILE','../downloads.log');