Carrier Wave mini_magick_processing error

I am trying to upload an image in my signup form using carrier =wave gem but getting this error .. ??

'Avatar translation missing: en.errors.messages.mini_magick_processing_error'

This is my form

    <%= form_for @user do |f| %>

    <%= f.label :avatar %>
    <%= f.file_field :avatar %>
    <%= f.submit "SignUp", class: "btn btn-primary button" %>

   <% end %>
   <%= image_tag @user.avatar.url %>

and this is my Avatar_uploader

class AvatarUploader < CarrierWave::Uploader::Base

# Include RMagick or MiniMagick support: # include CarrierWave::RMagick include CarrierWave::MiniMagick

# Choose what kind of storage to use for this uploader: storage :file # storage :fog

# Override the directory where uploaded files will be stored. # This is a sensible default for uploaders that are meant to be mounted: def store_dir "uploads/#{model.class.to_s.underscore}/#{mounted_as}/#{model.id}" end

# Provide a default URL as a default if there hasn't been a file uploaded: # def default_url # # For Rails 3.1+ asset pipeline compatibility: # # ActionController::Base.helpers.asset_path("fallback/" + [version_name, "default.png"].compact.join('_')) # # "/images/fallback/" + [version_name, "default.png"].compact.join('_') # end

# Process files as they are uploaded: # process scale: [200, 300] # def scale(width, height) # # do something end

# Create different versions of your uploaded files: version :thumb do process resize_to_fit: [50, 50] end

# Add a white list of extensions which are allowed to be uploaded. # For images you might use something like this: def extension_whitelist %w(jpg jpeg gif png) end

# Override the filename of the uploaded files: # Avoid using model.id or version_name here, see uploader/store.rb for details. # def filename # "something.jpg" if original_filename # end

end