Redmine

I am new to redmine but am trying to install Redmine as a win32 service (http://www.redmine.org/projects/redmine/wiki/HowTo_run_Redmine_as_a_Windows_service_(win32-service_+_taskill_approach))

I can register the service ok on my win 8.1 machine but cannot start it. I check the logs and it says:

***Daemon failure 2014-08-22 11:33:09 +0200 exception=#<LoadError: cannot load such file -- win32/daemon>
C:/Ruby200-x64/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
C:/Ruby200-x64/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
C:/redmine/service.rb:5:in `<main>'

I have tried with the command gem install win32-service but that also fails with error:

Error: While executing gem ... (Errno::Eacces)
Permission denied - Y:/.gem

Appreciate all help