Uninitialized constant Mime::PDF using Wicked PDF gem / Rails 3 project

I'm getting this error when I try to submit my form (PDF is supposed to be generated using Wicked PDF gem, on form submission) - ``` NameError in PostsController#create uninitialized constant Mime::PDF Rails.root: /Users/fkhalid2008/littlechits Application Trace | Framework Trace | Full Trace app/controllers/posts_controller.rb:42:in `create' app/controllers/posts_controller.rb:39:in `create' ``` How do I fix this??? Relevant code is below. POSTS CONTROLLER ``` def create @post = Post.new(params[:post]) @post.user = current_user respond_to do |format| if verify_recaptcha && @post.save format.html { redirect_to :action=> "index"} format.pdf do render :pdf => "file_name" end else format.html { render :action => "new" } format.json { render :json => @post.errors, :status => :unprocessable_entity } end end end ``` CONFIG/INITIALIZERS/WICKED_PDF.RB ``` # config/initializers/wicked_pdf.rb WickedPdf.config = { :exe_path => '/usr/local/bin/wkhtmltopdf' } ``` Thanks, Faisal