Index: biblio.import.export.inc
===================================================================
--- biblio.import.export.inc	(revision 4460)
+++ biblio.import.export.inc	(working copy)
@@ -1114,7 +1114,7 @@
   $fieldnames = null;
   foreach ((array)$result_array as $rec) {
     if (empty($fieldnames)) {
-      $fieldnames = array_keys($rec);
+      $fieldnames = array_keys((array)$rec);
       $csv .= biblio_strcsv($fieldnames);
     }
     $csv .= biblio_strcsv($rec);