Ruby on Rails : Error when trying generating template (AdminLTE2)

Please help me, i'm a new ruby/rails programmer, and I want to try a free dashboard admin (AdminLTE2), but i got a problem when trying to install it, i can generate it,

im already add "gem 'adminlte2-rails'" to Gemfile, and the gem was successfully deteced in rails generate option.

i have already googling the error code too, but found nothing.

i'm using all newest ruby(2.2.2) technology, gem 2.4.8, rails 4.2.1. Thanks and sorry for my bad English.

g40@Lenovo-G40:~/Sites/TestSites$ bin/rails generate admin_lte2
 insert  app/assets/stylesheets/application.scss
/home/g40/.rvm/gems/ruby-2.2.2/gems/thor-0.19.1/lib/thor/actions/inject_into_file.rb:98:in `binread': No such file or directory @ rb_sysopen - /home/g40/Sites/TestSites/app/assets/stylesheets/application.scss (Errno::ENOENT)
from /home/g40/.rvm/gems/ruby-2.2.2/gems/thor-0.19.1/lib/thor/actions/inject_into_file.rb:98:in `replace!'
from /home/g40/.rvm/gems/ruby-2.2.2/gems/thor-0.19.1/lib/thor/actions/inject_into_file.rb:59:in `invoke!'
from /home/g40/.rvm/gems/ruby-2.2.2/gems/thor-0.19.1/lib/thor/actions.rb:94:in `action'
from /home/g40/.rvm/gems/ruby-2.2.2/gems/thor-0.19.1/lib/thor/actions/inject_into_file.rb:30:in `insert_into_file'
from /home/g40/.rvm/gems/ruby-2.2.2/gems/adminlte2-rails-0.0.6/lib/generators/admin_lte2/admin_lte2_generator.rb:8:in `main'
from /home/g40/.rvm/gems/ruby-2.2.2/gems/thor-0.19.1/lib/thor/command.rb:27:in `run'
from /home/g40/.rvm/gems/ruby-2.2.2/gems/thor-0.19.1/lib/thor/invocation.rb:126:in `invoke_command'
from /home/g40/.rvm/gems/ruby-2.2.2/gems/thor-0.19.1/lib/thor/invocation.rb:133:in `block in invoke_all'
from /home/g40/.rvm/gems/ruby-2.2.2/gems/thor-0.19.1/lib/thor/invocation.rb:133:in `each'
from /home/g40/.rvm/gems/ruby-2.2.2/gems/thor-0.19.1/lib/thor/invocation.rb:133:in `map'
from /home/g40/.rvm/gems/ruby-2.2.2/gems/thor-0.19.1/lib/thor/invocation.rb:133:in `invoke_all'
from /home/g40/.rvm/gems/ruby-2.2.2/gems/thor-0.19.1/lib/thor/group.rb:232:in `dispatch'
from /home/g40/.rvm/gems/ruby-2.2.2/gems/thor-0.19.1/lib/thor/base.rb:440:in `start'
from /home/g40/.rvm/gems/ruby-2.2.2/gems/railties-4.2.1/lib/rails/generators.rb:157:in `invoke'
from /home/g40/.rvm/gems/ruby-2.2.2/gems/railties-4.2.1/lib/rails/commands/generate.rb:13:in `<top (required)>'
from /home/g40/.rvm/gems/ruby-2.2.2/gems/activesupport-4.2.1/lib/active_support/dependencies.rb:274:in `require'
from /home/g40/.rvm/gems/ruby-2.2.2/gems/activesupport-4.2.1/lib/active_support/dependencies.rb:274:in `block in require'
from /home/g40/.rvm/gems/ruby-2.2.2/gems/activesupport-4.2.1/lib/active_support/dependencies.rb:240:in `load_dependency'
from /home/g40/.rvm/gems/ruby-2.2.2/gems/activesupport-4.2.1/lib/active_support/dependencies.rb:274:in `require'
from /home/g40/.rvm/gems/ruby-2.2.2/gems/railties-4.2.1/lib/rails/commands/commands_tasks.rb:123:in `require_command!'
from /home/g40/.rvm/gems/ruby-2.2.2/gems/railties-4.2.1/lib/rails/commands/commands_tasks.rb:130:in `generate_or_destroy'
from /home/g40/.rvm/gems/ruby-2.2.2/gems/railties-4.2.1/lib/rails/commands/commands_tasks.rb:50:in `generate'
from /home/g40/.rvm/gems/ruby-2.2.2/gems/railties-4.2.1/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
from /home/g40/.rvm/gems/ruby-2.2.2/gems/railties-4.2.1/lib/rails/commands.rb:17:in `<top (required)>'
from /home/g40/.rvm/gems/ruby-2.2.2/gems/activesupport-4.2.1/lib/active_support/dependencies.rb:274:in `require'
from /home/g40/.rvm/gems/ruby-2.2.2/gems/activesupport-4.2.1/lib/active_support/dependencies.rb:274:in `block in require'
from /home/g40/.rvm/gems/ruby-2.2.2/gems/activesupport-4.2.1/lib/active_support/dependencies.rb:240:in `load_dependency'
from /home/g40/.rvm/gems/ruby-2.2.2/gems/activesupport-4.2.1/lib/active_support/dependencies.rb:274:in `require'
from /home/g40/Sites/TestSites/bin/rails:8:in `<top (required)>'
from /home/g40/.rvm/gems/ruby-2.2.2/gems/activesupport-4.2.1/lib/active_support/dependencies.rb:268:in `load'
from /home/g40/.rvm/gems/ruby-2.2.2/gems/activesupport-4.2.1/lib/active_support/dependencies.rb:268:in `block in load'
from /home/g40/.rvm/gems/ruby-2.2.2/gems/activesupport-4.2.1/lib/active_support/dependencies.rb:240:in `load_dependency'
from /home/g40/.rvm/gems/ruby-2.2.2/gems/activesupport-4.2.1/lib/active_support/dependencies.rb:268:in `load'
from /home/g40/.rvm/rubies/ruby-2.2.2/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:54:in `require'
from /home/g40/.rvm/rubies/ruby-2.2.2/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:54:in `require'
from -e:1:in `<main>'