diff --git includes/bootstrap.inc includes/bootstrap.inc
index 8b463b6..e4e95ef 100644
--- includes/bootstrap.inc
+++ includes/bootstrap.inc
@@ -917,6 +917,9 @@ function drupal_add_http_header($name = NULL, $value = NULL, $append = FALSE) {
   // The headers as name/value pairs.
   $headers = &drupal_static(__FUNCTION__, array());
 
+  if (isset($value) && empty($name)) {
+    throw new Exception('In Drupal 7, headers are passed in as key:value pairs.  For example: $headers = array("Content-type" => "application/octet-stream").');
+  }
   if (!isset($name)) {
     return $headers;
   }