In this short post I'll show you how to troubleshoot the error:
E370: Could not load library msvctr-ruby200.dll
If you had install Commant-T on Windows (the right way) and are seeing the afore mention error, chances are you had installed the x64 version of Ruby 2.0 and Ruby Dev Kit. I had made the same mistake (several times!), so no worries, you are just an easy fix away from fixit. Just uninstall the x64 version and install the x86 one of both, Ruby and RubyDevKit.
Once you had installed the right version (platform wise), open vim and run:
:ruby puts RUBY_VERSION.
You shouldn't get any errors any everything should work as expected.
* Verify the contents of C:\ruby200\bin (in there you should see msvctr-ruby200.dll).
* Close all instances of cmd and run Vim from a fresh new one.
If you have any question, ping me; I'll be glad to help.