Hi Renee
To allow our many business contacts to upload and download files on our SME, we have installed Mambo, DocMan and UberUpload running a website.
The Mambo admin interface allows creation of its own internal user database with individual upload/download rights for each user.
We find that our clients prefer to use browsers rather than ftp software and these Mambo Username/Password combinations give no access to the SME server OS.
This may be an alternative approach to solve your situation.
HTH, David.