diff --git a/lib/redmine_custom_workflows/mailer_patch.rb b/lib/redmine_custom_workflows/mailer_patch.rb
index 863ed23..cc02d50 100644
--- a/lib/redmine_custom_workflows/mailer_patch.rb
+++ b/lib/redmine_custom_workflows/mailer_patch.rb
@@ -27,7 +27,7 @@ module RedmineCustomWorkflows
             format.html { render template_name } unless Setting.plain_text_mail?
           end
         else
-          raise 'Nor :text_body, :html_body or :template_name specified'
+          raise 'Not :text_body, :html_body or :template_name specified'
         end
       end
     end