--- drush/commands/core/core.drush.inc	Sat Oct 31 14:32:31 2009
+++ drush/commands/core/core.drush.inc.new	Sat Oct 31 14:35:12 2009
@@ -530,7 +530,7 @@ function core_watchdog_format_row($watch
     $severities[$watchdog->severity],
     dt($watchdog->type),
     core_watchdog_format_message($watchdog),
-    strip_tags(theme('username', $watchdog)),
+    strip_tags(theme('username', (array)$watchdog)),
   );
 }