Recurring Error: A connection attempt failed...

I get the following error when connection to a number of different FTP hosts run by different companies (HostGator, DreamHost, etc):

A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.

I'm running Windows 7 Home Premium, and am on a wired home network (the router's hardware firewall is not enabled).

Full log:

[14:09:57] SmartFTP v4.0.1140.0

[14:09:58] Resolving host name "www.example.com"

[14:09:58] Connecting to 111.222.333.444 Port: 21

[14:09:58] Connected to www.example.com.

[14:09:58] 220 DreamHost FTP Server

[14:09:58] USER blahblah

[14:09:58] 331 Password required for blahblah.

[14:09:58] PASS (hidden)

[14:09:59] 230 User blahblah logged in.

[14:09:59] SYST

[14:10:00] 215 UNIX Type: L8

[14:10:00] Detected Server Type: UNIX

[14:10:00] RTT: 255.263 ms

[14:10:00] FEAT

[14:10:00] 211-Features:

[14:10:00]  MDTM

[14:10:00]  REST STREAM

[14:10:00]  SIZE

[14:10:00] 211 End

[14:10:00] PWD

[14:10:00] 257 "/" is current directory.

[14:10:00] CWD /example.com

[14:10:01] 250 CWD command successful

[14:10:01] PWD

[14:10:01] 257 "/example.com" is current directory.

[14:10:01] TYPE A

[14:10:01] 200 Type set to A

[14:10:01] PASV

[14:10:01] 227 Entering Passive Mode (111,222,333,444,207,99).

[14:10:01] Opening data connection to 111.222.333.444 Port: 53091

[14:10:01] LIST -aL

[14:10:22] A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.