Redmine

After the upgrade, all works except the view "issues". This seems to be like this bug http://www.redmine.org/boards/2/topics/17304 but i don't know how to check if the "route.rb" file is corrupted ??

ActionView::TemplateError (undefined method `-' for nil:NilClass) on line #16 of app/views/issues/_list.rhtml:
13:     </tr></thead>
14:     <% previous_group = false %>
15:     <tbody>
16:     <% issue_list(issues) do |issue, level| -%>
17:   <% if @query.grouped? && (group = @query.group_by_column.value(issue)) != previous_group %>
18:     <% reset_cycle %>
19:     <tr class="group open">

    app/helpers/issues_helper.rb:28:in `issue_list'
    app/helpers/issues_helper.rb:23:in `each'
    app/helpers/issues_helper.rb:23:in `issue_list'
    app/views/issues/_list.rhtml:16
    app/views/issues/_list.rhtml:1:in `_run_rhtml_app47views47issues47_list46rhtml_locals_issues_list_object_query'
    app/views/issues/index.rhtml:62:in `_run_rhtml_app47views47issues47index46rhtml'
    app/controllers/issues_controller.rb:83
    app/controllers/issues_controller.rb:82:in `index'
    public/dispatch.fcgi:24

thanks in advance.