Problems with sftp

I've finally removed the functionality of FTP to the server, and now have problems with specific users in getting them to implement the sftp in their PC Tools (CuteFTP, Smart FTP, WS FTP - which I'm using).

There are no logs for errors which I am able to locate. I can verify Authentication on the server, but when the users attempt to transfer files to the server, they create an empty file. No Contents, just empty.

Has anyone experienced the problem with educating an inexperienced population on the changes for sftp, and can I examine the problems they are experiencing in the logs (I cannot find them!).

TIA

-- 
Albert E. Whale, CISSP
http://www.abs-comptech.com
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ABS Computer Technology, Inc. - ESM, Computer & Networking Specialists
Sr. Security, Network, and Systems Consultant
Founding Board of Directors of Pittsburgh FBI - InfraGard