A good web download manager?

I'm looking for a nice open source download manager web application. Basically a web interface for some files on a Linux server file system. I looked at sourceforge and google couldn't find a good one. Maybe I am looking for it with the wrong keywords?

PHP is preferred but can be written in other programming languages ​​as well.

Some of the features I'm looking for:

• Possibility of users and user groups with login and password;
• Downloading and deleting files in the file system from the web interface;
• Set permission on uploaded files or group of files based on users or user group;
• List of files;
• Templates are relatively easy to adapt;

Thank!