In case others have this same problem.
My Nexpose API ruby scripts stopped working. Authentication failed b/c the script was using a version of SSL or TLS that is vulnerable, and my Nexpose server didn't allow it. (We keep that server patched too!) So... I installed the latest version of Ruby that is pre-built for windows, 2.1.5. (looks like none of the differences between 2.2.0 and 2.1.5 are related to SSL or TLS, so it should be good). After that, I had to reinstall my gems. Nexpose now requires the Nokogiri gem, which has never caused a problem for me in the past. But, this time, I am encountering all sorts of problems installing the Nokogiri gem, including conflicting information (the gem website says not to use DevKit, but the gem installer told me I needed to have DevKit).
The solution appears to be simple. Before installing the nokogiri gem, run gem update
Hope this saves others the hours it cost me...