HandyBackup 7.4 & ReadyNAS OS 6.1

It was working. There were internet connection problems at the remote location. A Comcast tech came out, did some work, put in a new router/modem combo. I setup NAT on the new router to forward the same ports as the old router was forwarding: 443 (HTTPS), 21 (FTP), and 55000-55100 (FTP passive ports). I can remotely connect to the NAS' web management interface through HTTPS.

When I connect from the Windows Server 2003R2 SP2 command prompt I get:
C:\>FTP [NAS IP]
Connected to [NAS IP].
220 ProFTPD 1.3.4c Server (NETGEAR ReadyNAS) [NAS IP]
User ([NAS IP]:(none)): SQL2
331 Password required for SQL2
Password:
230 User SQL2 logged in
ftp> dir
200 PORT command successful
150 Opening ASCII mode data connection for file list
drwxrwxrwx 1 guest guest 270 Aug 26 13:29 Backup
226 Transfer complete
ftp: 63 bytes received in 0.00Seconds 63000.00Kbytes/sec.
ftp>

When I try from my Windows 7 Pro x64 SP1 desktop I get:
C:\>ftp [NAS IP]
Connected to [NAS IP].
220 ProFTPD 1.3.4c Server (NETGEAR ReadyNAS) [NAS IP]
User ([NAS IP]:(none)): SQL2
331 Password required for SQL2
Password:
230 User SQL2 logged in
ftp> dir
500 PORT/EPRT (Active Mode/Extended Active Mode) is not supported. Use PASV/EPSV
instead of this
425 Unable to build data connection: Invalid argument
ftp> PASV
Invalid command.
ftp>

FileZilla works fine from my desktop.