This funny port number is coming from the NAT operations in your firewall. There are ways to maneuver Amanda around that, but you might be better served to simply use ssh authentication, if that's an option. Otherwise, you should either set up a static NAT on the firewall or set the Amanda client's port ranges "wide open" (1024-65535, or to whatever your firewall's range of dynamically assigned ports happens to be).
Dustin -- Storage Software Engineer http://www.zmanda.com