Index: handlers/views_handler_field.inc
===================================================================
RCS file: /cvs/drupal-contrib/contributions/modules/views/handlers/views_handler_field.inc,v
retrieving revision 1.6
diff -u -r1.6 views_handler_field.inc
--- handlers/views_handler_field.inc	30 Jan 2009 00:01:41 -0000	1.6
+++ handlers/views_handler_field.inc	30 Jan 2009 12:38:00 -0000
@@ -594,7 +594,12 @@
  */
 class views_handler_field_file_size extends views_handler_field {
   function render($values) {
-    return format_size($values->{$this->field_alias});
+    if ($values->{$this->field_alias}) {
+      return format_size($values->{$this->field_alias});
+    }
+    else {
+      return '';
+    }
   }
 }