Codeigniter not creating any log files
The log filename in the configuration settings needs a trailing "/" above making sure the webserver process has writeable access to the directory.
Change the logs owner and group to what owner/group your live web server is running, give it write perms and it should work. I take it that in your local/dev server your CI folder is owned by you that is why you need to chmod it to 777 to make it work.