--- modules/user/user.module	2010-03-19 15:42:34.000000000 -0700
+++ modules/user/user.module	2010-03-19 15:42:17.000000000 -0700
@@ -2284,6 +2284,12 @@ function user_block_user_action(&$object
   }
   db_query("UPDATE {users} SET status = 0 WHERE uid = %d", $uid);
   sess_destroy_uid($uid);
+  if($user->name) {
+    $name = $user->name;
+  }
+  else {
+    $name = db_result(db_query("SELECT name FROM {users} WHERE uid = %d", $uid));
+  }
   watchdog('action', 'Blocked user %name.', array('%name' => check_plain($user->name)));
 }