Index: simplenews.module
===================================================================
RCS file: /cvs/drupal-contrib/contributions/modules/simplenews/simplenews.module,v
retrieving revision 1.76.2.133
diff -u -p -r1.76.2.133 simplenews.module
--- simplenews.module	9 Aug 2009 10:46:45 -0000	1.76.2.133
+++ simplenews.module	29 Aug 2009 12:29:53 -0000
@@ -1945,9 +1945,12 @@ function _simplenews_set_from($node = NU
     $name = variable_get('simplenews_from_name', $name_default);
   }
 
+  // Windows based PHP systems don't accept formatted emails.
+  $formatted_address = substr(PHP_OS, 0, 3) == 'WIN' ? $address : '"'. mime_header_encode($name) .'" <'. $address .'>';
+  
   return array(
     'address' => $address,
-    'formatted' => '"'. mime_header_encode($name) .'" <'. $address .'>',
+    'formatted' => $formatted_address,
   );
 }