Index: app/controllers/projects_controller.rb
===================================================================
--- app/controllers/projects_controller.rb	(revision 1118)
+++ app/controllers/projects_controller.rb	(working copy)
@@ -262,9 +262,13 @@
   def add_file
     if request.post?
       @version = @project.versions.find_by_id(params[:version_id])
+      if @version == nil
+        flash[:error] = l(:error_need_version_to_upload_file)
+      else
       attachments = attach_files(@version, params[:attachments])
       Mailer.deliver_attachments_added(attachments) if !attachments.empty? && Setting.notified_events.include?('file_added')
       redirect_to :controller => 'projects', :action => 'list_files', :id => @project
+      end
     end
     @versions = @project.versions.sort
   end
Index: lang/en.yml
===================================================================
--- lang/en.yml	(revision 1118)
+++ lang/en.yml	(working copy)
@@ -80,6 +80,7 @@
 error_can_t_load_default_data: "Default configuration could not be loaded: %s"
 error_scm_not_found: "Entry and/or revision doesn't exist in the repository."
 error_scm_command_failed: "An error occurred when trying to access the repository: %s"
+error_need_version_to_upload_file: "Version is required.  Create a Version if one doesn't exist."