ArgumentError on Rake task arguments

Rake now supports task arguments of the form:

task 'my_task', :arg1, :arg2 do |task, args|
  # do stuff
end

these tasks cause an ArgumentError in sake on import/export...

longer example

task 'ftp:sync_up', :remote_dir, :needs => [ 'ftp:init' ] do |t, args|
  # etc.
end