Index: simplenews_template.module
===================================================================
--- simplenews_template.module	(revision 415)
+++ simplenews_template.module	(working copy)
@@ -172,6 +172,7 @@ function simplenews_template_link_alter(
  * Overriding theme_simplenews_newsletter().
  */
 function phptemplate_simplenews_newsletter($node, $tid) {
+  require_once _simplenews_template_path('simplenews_template.inc');
   return _simplenews_template_newsletter($node, $tid);
 }
 
@@ -180,6 +181,7 @@ function phptemplate_simplenews_newslett
  * Overriding theme_mimemail_message().
  */
 function phptemplate_mimemail_message($content) {
+  require_once _simplenews_template_path('simplenews_template.inc');
   return _simplenews_template_message($content);
 }