--- drupalforfirebug.module	2011-01-06 20:26:58.000000000 +0300
+++ drupalforfirebug.module.new	2011-01-28 17:01:30.000000000 +0300
@@ -13,16 +13,18 @@ function drupalforfirebug_init() {
 function drupalforfirebug_exit() {
   $dff = TRUE;
 
-  // Try not to break non html pages. [from devel.module]
-  if (function_exists('drupal_get_headers')) {
-    $headers = drupal_get_headers();
-    $formats = array('xml', 'javascript', 'json', 'plain', 'image', 'application', 'csv', 'x-comma-separated-values');
-    foreach ($formats as $format) {
-      if (strstr($headers, $format)) {
-        $dff = FALSE;
+  // Try not to break non html pages. [from new devel.module]                     
+  if (function_exists('drupal_get_http_header')) {
+      $header = drupal_get_http_header('content-type');
+      if ($header) {
+        $formats = array('xml', 'javascript', 'json', 'plain', 'image', 'application', 'csv', 'x-comma-separated-values');
+        foreach ($formats as $format) {
+          if (strstr($header, $format)) {
+            $dff = FALSE;
+          }
+        }
       }
-    }
-                      }
+    }                    
 
   // Check with Devel if Installed
   if (module_exists('devel')) {