After creating a new AWS account, and switching to the new key/secret, I get this:

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
    An unexpected error has occurred.
  Please report the following lines to:
   s3tools-bugs@lists.sourceforge.net
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Problem: ValueError: incomplete format
S3cmd:   1.0.1

Traceback (most recent call last):
  File "/usr/local/bin/s3cmd", line 2006, in <module>
    main()
  File "/usr/local/bin/s3cmd", line 1795, in main
    cfg = Config(options.config)
  File "/usr/local/Cellar/s3cmd/1.0.1/libexec/S3/Config.py", line 88, in __init__
    self.read_config_file(configfile)
  File "/usr/local/Cellar/s3cmd/1.0.1/libexec/S3/Config.py", line 105, in read_config_file
    cp = ConfigParser(configfile)
  File "/usr/local/Cellar/s3cmd/1.0.1/libexec/S3/Config.py", line 142, in __init__
    self.parse_file(file, sections)
  File "/usr/local/Cellar/s3cmd/1.0.1/libexec/S3/Config.py", line 170, in parse_file
    print_value = (data["value"][:2]+"...%d_chars..."+data["value"][-1:]) % (len(data["value"]) - 3)
ValueError: incomplete format

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
    An unexpected error has occurred.
    Please report the above lines to:
   s3tools-bugs@lists.sourceforge.net
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!