hi..
first of all, no crystal ball here, so you should tell us how is your server configured (server only? server and gateway?)
then, is the sftp server running on SME or is it running on another machine? and, again, are the sites on SME?
finally, remember you cna not forward the same EXTERNAL port to many servers..
Ciao
Stefano
p.s. please take some time to read the documentation
