Index: affiliates.module
===================================================================
RCS file: /cvs/drupal-contrib/contributions/modules/affiliates/affiliates.module,v
retrieving revision 1.1.4.5.2.20
diff -r1.1.4.5.2.20 affiliates.module
1106c1106
<       if (strpos($_SERVER['HTTP_REFERER'], $referrer)) return TRUE;
---
>       if (!empty($referrer) && strpos($_SERVER['HTTP_REFERER'], $referrer)) return TRUE;