new to rails with a plugin question

Hey Everybody, i am trying to use the rails plugin ym4r_gm and nothing i do seems to be working, and the error i am getting looks like rails isn't seeing the plugin. here is the error message: NoMethodError in Content_pages#view_default

Showing app/views/layouts/application.rhtml where line #14 raised: You have a nil object when you didn't expect it! The error occurred while evaluating nil.to_html

Extracted source (around line #14): 11: </title> 12: <%= stylesheet_link_tag "style", :media => "all" %> 13: <%= GMap.header %> 14: <%= @map.to_html %> 15: </head> 16: <body> 17: <div id="container">

RAILS_ROOT: script/../config/.. Application Trace | Framework Trace | Full Trace #{RAILS_ROOT}/app/views/layouts/application.rhtml:14:in `_run_rhtml_47app47views47layouts47application46rhtml'

if anybody could help me that would be awesome, i am stumped.