--- headinganchors.module	2008-02-15 13:32:12.000000000 -0500
+++ headinganchors_emptytags.module	2008-05-05 11:19:47.000000000 -0400
@@ -93,6 +93,9 @@ function headinganchors_filter($op, $del
           $anchor = preg_replace("/[^A-Za-z0-9]/", "", $anchor);
           $anchor = preg_replace("/^[0-9]+/", "", $anchor);
         }
+        if (empty($anchor)) {
+          $anchor = 'a';
+		}
 
         // Look for duplicate ID's, and add -number to make them unique
         if (array_key_exists($anchor, $anchors)) {