Unable to install gem

[cgdichoso]

I'm relatively new to ruby and I was looking into installing this gem but I keep getting the below messages:

---

ERROR: Error installing te3270-0.8.1.gem:
ERROR: Failed to build gem native extension.

current directory: C:/Tools/Ruby22-x64/lib/ruby/gems/2.2.0/gems/te3270-0.8.1/ext
C:/Tools/Ruby22-x64/bin/ruby.exe mkrf_conf.rb
mkrf_conf.rb: Unable to resolve dependency: user requested 'win32screenshot (>= 0)'

rake failed, exit code 1

[aseward44]

I am experiencing the same issue as above when attempting the gem install. It's unable to resolve the dependency on the win32screenshot gem, however, I manually installed win32screenshot versions 2.1.0 and 2.0.0 into my library and they are on my gem list. Any ideas on what could be tripping this up?