Index: adsense/adsense.module
===================================================================
--- adsense/adsense.module	(revision 6961)
+++ adsense/adsense.module	(working copy)
@@ -641,7 +641,9 @@
   $alt      = variable_get(ADSENSE_ALT .          $group, 0);
   $alt_info = variable_get(ADSENSE_ALT_INFO .     $group, '');
 
-  $channel = variable_get(ADSENSE_AD_CHANNEL . _adsense_validate_channel($channel), '');
+  if (!is_string($channel)) {
+    $channel = variable_get(ADSENSE_AD_CHANNEL . _adsense_validate_channel($channel), '');
+  }
 
   switch (variable_get(ADSENSE_AD_TYPE . $group, '0')) {
     case 2: