In order to use RunSignup, your browser must accept cookies. Otherwise, you will not be able to register for races or use other functionality of the website. However, your browser doesn't appear to allow cookies by default.
If you still see this message after clicking the link, then your browser settings are likely set to not allow cookies. Please try enabling cookies. You can find instructions at https://www.whatismybrowser.com/guides/how-to-enable-cookies/auto.
You can use a custom section on the race page to promote your referral program. To add a custom section go to Race>>Race Page>>Custom Content/Pages. Click the "Add Custom Section/Page" button.