Redmine

when I new an issue and input some codes like

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

an Internal error was raised

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'