diff --git a/app/views/periodictask/_form.html.erb b/app/views/periodictask/_form.html.erb
index d253471..6c701aa 100644
--- a/app/views/periodictask/_form.html.erb
+++ b/app/views/periodictask/_form.html.erb
@@ -28,7 +28,7 @@
     <%= l(:no_members_in_project) %>
   <% end %>
 </p>
-<p><%= label(:periodictask, :interval_number, l(:label_interval)) %><%= f.text_field :interval_number, :required=> true, :size => 3 %> <%= select 'periodictask', 'interval_units', Periodictask::INTERVAL_UNITS %></p>
+<p><%= label(:periodictask, :interval_number, l(:label_interval)) %><%= f.number_field :interval_number, :value => 1, :required => true, :min => 1 %> <%= select 'periodictask', 'interval_units', Periodictask::INTERVAL_UNITS %></p>
 <p><%= label(:periodictask, :tracker_id, "Tracker") %><%= collection_select("periodictask", "tracker_id", @project.trackers, :id, :name ) %></p>
 <p><%= label(:periodictask, :set_start_date, l(:label_set_start_date)) %><%= f.check_box :set_start_date %> </p>
 <p><%= label(:periodictask, :due_date, l(:label_due_date)) %><%= f.text_field :due_date_number, :size => 3 %><%= select 'periodictask', 'due_date_units', Periodictask::INTERVAL_UNITS %></p>
diff --git a/lib/scheduled_tasks_checker.rb b/lib/scheduled_tasks_checker.rb
index bd08580..9cc9ea9 100644
--- a/lib/scheduled_tasks_checker.rb
+++ b/lib/scheduled_tasks_checker.rb
@@ -39,8 +39,10 @@ def self.checktasks!
       if units.downcase == "business_day"
         task.next_run_date = task.interval_number.business_day.after(now)
       else
-        interval_steps = ((now - task.next_run_date) / interval.send(unit_to_use)).ceil
-        task.next_run_date += (interval * interval_steps).send(units.downcase)
+        if (interval > 0)
+          interval_steps = ((now - task.next_run_date) / interval.send(units.downcase)).ceil
+          task.next_run_date += (interval * interval_steps).send(units.downcase)
+        end
       end
       task.save
     end