Redmine

when I new an issue and input some codes like

<pre><code class="C">
some codes
</code>

Internal error

An error occurred on the page you were trying to access.
If you continue to experience problems please contact your redMine administrator for assistance.

Exception Stack:

ActionView::TemplateError (No CodeRay::Scanners plugin for :C found in C:/redmine/vendor/plugins/coderay-0.7.6.227/lib/coderay/scanners/C.rb.) on line
 #2 of common/_preview.rhtml:
1: <fieldset class="preview"><legend><%= l(:label_preview) %></legend>
2: <%= textilizable @text, :attachments => @attachements %>
3: </fieldset>

    vendor/plugins/coderay-0.7.6.227/lib/coderay/helpers/plugin.rb:200:in `creat
e_plugin_hash'
    vendor/plugins/coderay-0.7.6.227/lib/coderay/helpers/plugin.rb:51:in `call'
    vendor/plugins/coderay-0.7.6.227/lib/coderay/helpers/plugin.rb:51:in `defaul
t'
    vendor/plugins/coderay-0.7.6.227/lib/coderay/helpers/plugin.rb:51:in `[]'
    vendor/plugins/coderay-0.7.6.227/lib/coderay/helpers/plugin.rb:51:in `[]'
    vendor/plugins/coderay-0.7.6.227/lib/coderay.rb:156:in `scan'
    lib/redmine/wiki_formatting.rb:59:in `smooth_offtags'
    lib/redmine/wiki_formatting.rb:55:in `gsub!'
    lib/redmine/wiki_formatting.rb:55:in `smooth_offtags'
    lib/redcloth.rb:305:in `to_html'
    lib/redmine/wiki_formatting.rb:40:in `to_html'
    lib/redmine/wiki_formatting.rb:165:in `to_html'
    app/helpers/application_helper.rb:221:in `textilizable'
    app/views/common/_preview.rhtml:2:in `_run_erb_47app47views47common47_previe
w46rhtml'
    C:/TracLight/ruby/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_view/ba
se.rb:637:in `send'
    C:/TracLight/ruby/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_view/ba
se.rb:637:in `compile_and_render_template'