rails 4.2 assets precompilation issue – Twitter bootstrap

i’m testing the deployment af RoR 4.2.x app…

when i execute it in development all runs fine,
if i simulate deployment on a vm to prepare final deployment phase,
i receive an error during asset precompilation….

the deployment env is ubuntu 14.04 lts server using rvm, passenger and Apache as web server..

after all needed library updates (as prerequisites) i’ve done a checkout of the repo to the working dir onto web server,
then correctly executed ‘bundle update’ inside the working dir to correctly populate the gemset…

during this phase no errors are returned from the server console, all seems to run fine…

if i run ‘gem list’ all needed gems results present

now, precompiling assets using the command:

RAILS_ENV=production bundle exec rake assets:precompile

the operation aborts after few seconds with this error:

rake aborted!
Sprockets::FileNotFound: couldn't find file 'jquery-ui' with type 'application/javascript'
/home/rails-usr/www_v2/app/assets/javascripts/application.js:10
/home/rails-usr/.rvm/gems/ruby-2.2.2@Best-i-gest_v2/gems/sprockets-3.6.2/lib/sprockets/resolve.rb:64:in `resolve!'
/home/rails-usr/.rvm/gems/ruby-2.2.2@Best-i-gest_v2/gems/sprockets-3.6.2/lib/sprockets/directive_processor.rb:399:in `resolve'
/home/rails-usr/.rvm/gems/ruby-2.2.2@Best-i-gest_v2/gems/sprockets-3.6.2/lib/sprockets/directive_processor.rb:207:in `process_require_directive'
.....

going to add some more info to my question…

here is my app ‘Gemfile’

source 'http://rubygems.org'

gem 'rails', '4.2.5'

gem 'mysql2', '0.3.17'
gem 'bcrypt-ruby', :require => 'bcrypt'
gem 'declarative_authorization', :git => 'git://github.com/stffn/declarative_authorization'
gem 'ruby_parser'
gem 'jQuery-Validation-Engine-rails'
gem 'prawn', '1.3.0'
gem 'prawn-table', '0.2.1'

# gem 'bootstrap-sass', '~> 3.1.1'

# Gems used only for assets and not required
# in production environments by default.
group :assets do
  gem 'sass-rails'
  gem 'coffee-rails'
  gem 'uglifier'

  gem "therubyracer"
  gem "less-rails", :git => 'git://github.com/metaskills/less-rails', :ref => '539f28d'

  gem 'jquery-datatables-rails' , :git => 'git://github.com/rweng/jquery-datatables-rails'
  gem 'jquery-ui-rails'
end

gem 'twitter-bootstrap-rails', :git => 'git://github.com/coppolaf/tb3-rails4.git'

gem 'jquery-rails'
gem 'will_paginate'
gem 'nokogiri'

# To use debugger
# gem 'ruby-debug19', :require => 'ruby-debug'

group :test do
  # Pretty printed test output
  gem 'turn', '~> 0.8.3', :require => false
end

this is ‘application.js’ file:

// This is a manifest file that'll be compiled into including all the files listed below.
// Add new JavaScript/Coffee code in separate files in this directory and they'll automatically
// be included in the compiled file accessible from http://example.com/assets/application.js
// It's not advisable to add code directly here, but if you do, it'll appear at the bottom of the
// the compiled file.
//
//= require jquery
//= require jquery-ui
//= require jquery_ujs
//= require dataTables/jquery.dataTables
//= require twitter/bootstrap
//= require jquery.validationEngine
//= require_tree .
....

this is ‘application.css’ file:

/*
 * This is a manifest file that'll automatically include all the stylesheets available in this directory
 * and any sub-directories. You're free to add application-wide styles to this file and they'll appear at
 * the top of the compiled file, but it's generally better to create a new file per style scope.
 *= require_self
 *= require jquery-ui
 *= require dataTables/src/demo_table_jui
 *= bootstrap_and_overrides.css.less
 *= require validationEngine.jquery
 *= require_tree .
 */
....

pls note all jquery modules runs fine in development, the requested module seems to be present inside gemset….

waiting your suggestions,

regards,
francesco