ftools.rb
#########
  def move from, to, verbose = false
    to = catname(from, to)
    $deferr.print from, " -> ", to, "\n" if verbose

    if RUBY_PLATFORM =~ /djgpp|(cyg|ms|bcc)win|mingw/ and FileTest.file? to
      unlink to
    end
    fstat = stat(from)
    begin
      rename from, to
    rescue
      begin
        symlink File.readlink(from), to and unlink from
      rescue
        from_stat = stat(from)
        syscopy from, to and unlink from
        utime(from_stat.atime, from_stat.mtime, to)
        begin
          chown(fstat.uid, fstat.gid, to)
        rescue
        end
      end
    end
  end

If the rename call fails for something like "Permission denied" -- then 
the rescue clause tries to do a .readlink which is not supported on 
Windows. Ruby raises that error, and the original exception is hidden. 
I'm guessing a fix would be to do a platform regex like earlier in the 
method and not attempt the link related items if on Windows, etc.

Workaround is just to use File.rename instead.

-- 

Chris
http://clabs.org/blogki