Ruby on rails 3 Rails heroku错误为零

我的应用程序在开发中的iMac上运行良好。 但是，我在Heroku上得到以下错误（这是Heroku日志）：

ActionView:：Template:：Error（nil:NilClass的未定义方法“name”）：
22:         
23:         
24:         
25:             
app/views/home/_myopenorders.html.erb:25:in'block in_app_views_home_myopenorders_html_erb_1134835514768073858_64792180'
app/views/home/index.html.erb:66:in`_app\u views\u home\u index\u html\u erb\u 3327722386939287121\u 60092520'
26:         
27:             
app/views/home/_myopenorders.html.erb:15:in`_app_views_home_myopenorders_html_erb_1134835514768073858_64792180'
28:         

代码如下：

    <% if workorder.location_id != nil %>
        <td><%= workorder.location.name %></td>
    <% else %>
        <td></td>
    <% end %>

有什么想法吗

更新：

有时，日志看起来像是Heroku在无序运行ruby代码。看看这个：

  ActionView::Template::Error (undefined method `name' for nil:NilClass):
      22:         <% end %>
      26:         <% else %>
    app/views/home/index.html.erb:66:in `_app_views_home_index_html_erb__2268065945584360823_49285320'

    app/views/home/_myopenorders.html.erb:25:in `block in _app_views_home__myopenorders_html_erb___3485426105947531181_51160960'
      27:             <td></td>

    app/views/home/_myopenorders.html.erb:15:in `_app_views_home__myopenorders_html_erb___3485426105947531181_51160960'
      28:         <% end %>
      24:         <% if workorder.location_id != nil %>

ActionView:：Template:：Error（nil:NilClass的未定义方法“name”）：
22:         
26:         
app/views/home/index.html.erb:66:在`“应用程序”视图“主页”索引“html”erb“u2268065945584360823”中
app/views/home/_myopenorders.html.erb:25:in`block in_app_views_home_myopenorders_html_erb_34854261059475351181_51160960'
27:             
app/views/home/_myopenorders.html.erb:15:in`_app_views_home_myopenorders_html_erb_34854261059475731181_51160960'
28:         
24:         
对不起，是我的错。一个位置被删除，我没有代码来检查该位置是否被工单使用。
是，请提供更多代码：-）
  ActionView::Template::Error (undefined method `name' for nil:NilClass):
      22:         <% end %>
      26:         <% else %>
    app/views/home/index.html.erb:66:in `_app_views_home_index_html_erb__2268065945584360823_49285320'

    app/views/home/_myopenorders.html.erb:25:in `block in _app_views_home__myopenorders_html_erb___3485426105947531181_51160960'
      27:             <td></td>

    app/views/home/_myopenorders.html.erb:15:in `_app_views_home__myopenorders_html_erb___3485426105947531181_51160960'
      28:         <% end %>
      24:         <% if workorder.location_id != nil %>