Need help in Creating Redmine Uploader Plugin

I'm trying to create a redmine plugin that uploads files.

I used this tutorials:

http://www.tutorialspoint.com/ruby-on-rails/rails-file-uploading.htm

http://www.redmine.org/projects/redmine/wiki/Plugin_Tutorial

I already succeeded in uploading files using ruby on rails...
I want to integrate in a redmine plugin.

Here are my codes:

init.rb
Code:
require 'redmine'

Redmine::Plugin.register :redmine_pload do
  name ‘Redmine Pload plugin’
  author ‘Author name’
  description ‘This is a plugin for Redmine’
  version ‘0.0.1’
  url ‘http://example.com/path/to/plugin
  author_url ‘http://example.com/about
  menu :application_menu, :pload, { :controller => ‘pload’, :action =>
‘index’ }, :caption => ‘pload!’
end

pload_controller.rb
Code:
require 'redmine'

Redmine::Plugin.register :redmine_pload do
  name ‘Redmine Pload plugin’
  author ‘Author name’
  description ‘This is a plugin for Redmine’
  version ‘0.0.1’
  url ‘http://example.com/path/to/plugin
  author_url ‘http://example.com/about
  menu :application_menu, :pload, { :controller => ‘pload’, :action =>
‘index’ }, :caption => ‘pload!’
end

dota_file.rb
Code:
class DotaFile < ActiveRecord::Base
  unloadable

  def self.save(upload)
    name = upload['dotafile'].original_filename
    directory = "C:\Program Files\BitNami Redmine
Stack\apps\redmine\vendor\plugins\redmine_pload\public\data"
    # create the file path
    path = File.join(directory, name)
    # write the file
    File.open(path, "wb") { |f| f.write(upload['dotafile'].read) }
  end

  def self.filename(upload)
    wholename = String.new
    wholename = upload['dotafile'].original_filename
    return wholename
  end

end

index.html.rb
Code:
<h2>Pload#index</h2>

<h1>File Upload</h1>
<%= form_tag('uploadFile', :multipart => true) %>
<p><label for="upload_file">Select File</label> :
<%= file_field 'pload', 'datafile' %></p>
<%= submit_tag %>
<%= form_tag %>

my problem is... when i click the tab(link to plugin page) on redmine,
it jst shows this error.

Internal error

An error occurred on the page you were trying to access.
If you continue to experience problems please contact your redMine
administrator for assistance.

I am trying things to fix this for 3 days now, yet I have not found the
solution. Pls help me.