"IP Address for data destination doesn't match client's

I'm trying to transfer files between two Unix servers. I can FTP from and to each using the command line and also using Hummingbird FTP. However, when I use SmartFTP I get the following error"

501 IP Address for data destination doesn't match client's.

I assume this is a parameter I can adjust in SmartFTP, but I can't tell what it is. Thanks!

one of the servers dont allow fxp.

darix