Redmine

All of a sudden I am getting an error on line 53 in base.rhtml. Does anyone have any ideas on where to point me with regards to what specifically isn't a number? I'm not familiar with Ruby at all (I did import issues/etc from another system). This only happens when viewing the default issue report when clicking on the issue tab..... Thanks in advance:

ActionView::TemplateError (NaN) on line #53 of app/views/layouts/base.rhtml:
50: <%= tag('div', {:id => 'main', :class => (has_content?(:sidebar) ? '' : 'nosidebar')}, true) %>
51:     <div id="sidebar">        
52:         <%= yield :sidebar %>
53:         <%= call_hook :view_layouts_base_sidebar %>
54:     </div>
55:     
56:     <div id="content">

    app/helpers/application_helper.rb:631:in `collect'
    app/helpers/application_helper.rb:631:in `progress_bar'
    lib/redmine/hook.rb:63:in `send'
    lib/redmine/hook.rb:63:in `call_hook'
    lib/redmine/hook.rb:63:in `each'
    lib/redmine/hook.rb:63:in `call_hook'
    lib/redmine/hook.rb:60:in `call_hook'
    lib/redmine/hook.rb:144:in `call_hook'
    app/views/layouts/base.rhtml:53:in `_run_rhtml_app47views47layouts47base46rhtml'
    app/controllers/issues_controller.rb:78
    app/controllers/issues_controller.rb:77:in `index'

Rendering C:/Program Files/BitNami Redmine Stack/apps/redmine/public/500.html (500 Internal Server Error)