WebDAV Access Authorization

I have a single 2003 Server hosting web sites. Most are my own, several
belong to others. I have successfully been able to edit/modify website
content over internet connections from other locations using Front Page
2003. I have Sharepoint Services installed (appear to be correctly installed
too!)

I have tried to enable certain users the ability to access a WebDAV
folder pointed to an existing folder at my website on the server. I
cannot upload content remotely (this may be a clue) even though I am an
administrator. Could someone please point me in the right direction?