Cody,
The port forwarding application has no inspection to dynamically forward ports.
For active FTP, it won't work, as the DATA connection is initiated from the server back to the client, and the port forwarding application can't handle that.
For passive FTP, the port fowarding application doesn't know what random high port was chosen by the server.
Now, if your ftp server allows you to configure which port range to use for passive ftp (which I'm not sure of, it's not a standard feature AFAIK), you could in theory then statically port forward the individual ports in that range to the server to allow communication.
--Jason
