Uninitialized constant GEM (NameError)

Hi there,

I was given a little script to do some mailing testing to a test server
by a guy who no longer works with me.

I have used it before, but for some reason since changing to my Windows
7 X64 Desktop, Installing Ruby on Windows and trying to run the script,
I get the following:

nTools.rb:3: uninitialized constant GEM (NameError)

I see the script uses parseconfig so I installed ParseConfig as follows:
C:\Users\darylc\Desktop\nTools>gem install parseconfig
Successfully installed parseconfig-0.5.2
1 gem installed
Installing ri documentation for parseconfig-0.5.2…
Installing RDoc documentation for parseconfig-0.5.2…

After that, I still get the same error message. Any Suggestions?