No.
PHP cannot access the remote computers hard-disk, this is quite obvious. (Would you like to visit a website that keeps a listing of all your private documents etc?)
However, there are techniques that can be used in "special cases". PHP can access files on the machines it run on. So what you need to do, is make the files available there.
I.e., you can install the samba suite (http://www.samba.org, assuming you're using *nix on the server). You can then share directories on the workstation, and mount them to the server. I.e.,
'server' is running php + samba
'client' is running wintendo, has a share named 'public' wich contains documents you want to show on the web.
So, server mounts \client\public to a local directory, i.e. /mnt/smbweb/client. Your php script will then get a direcoty listing from /mnt/smbweb/client, wich contains all the files in the 'public' share on 'client'.
Of course, this is one hell of a hazzle.
If your server runs on a microsoft OS, you may be able to use opendir("\client\public"), although I've never tried it (or running php on windows for that matter). If this doesn't work out, you can use "net use <driveletter> \client\public", where driveletter being a free drive letter on 'server'. This ofcourse, limits you to 26, minus the number of local drive letters, clients.
