I have Joomla 1.5 installed on Fedora 8, MySQL 5, etc. Docman plugin (latest available) in installed for document management. It works in all respects EXCEPT that users cannot download any files. Neither can administrators. Files appear as if they are not linked to anything. ALL files in Joomla (including DocMan) are 777. Interestingly one can upload files in DocMan perfectly well, just not download.
I've installed and re-installed DocMan and then entire Joomla setup many times, still no joy.