Redmine

Version Info:
Redmine 1.0.4
(
Rails 2.3.5
Ruby 1.8.7
Mysql 5.1.53
)

Log Info:

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:in `_run_rhtml_app47views47issues47_list46rhtml_locals_issues_list_object_query'
    app/views/issues/_list.rhtml:1:in `_run_rhtml_app47views47issues47_list46rhtml_locals_issues_list_object_query'
    app/views/issues/index.rhtml:63:in `_run_rhtml_app47views47issues47index46rhtml'
    app/controllers/issues_controller.rb:84:in `index'
    app/controllers/issues_controller.rb:83:in `index'

Rendering D:/wServer/Redmine/public/500.html (500 Internal Server Error)