私はubuntuでこの行を実行しています：
sudo apt-get install pptpd
そして、ここに私が得る出力があります：
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following extra packages will be installed:
bcrelay
The following NEW packages will be installed:
bcrelay pptpd
0 upgraded, 2 newly installed, 0 to remove and 0 not upgraded.
Need to get 96.2 kB of archives.
After this operation, 446 kB of additional disk space will be used.
Do you want to continue [Y/n]? y
Err http://us-west-1.ec2.archive.ubuntu.com/ubuntu/ natty/main bcrelay amd64 1.3.4-3ubuntu1
403 Forbidden
Err http://us-west-1.ec2.archive.ubuntu.com/ubuntu/ natty/main pptpd amd64 1.3.4-3ubuntu1
403 Forbidden
Failed to fetch http://us-west-1.ec2.archive.ubuntu.com/ubuntu/pool/main/p/pptpd/bcrelay_1.3.4-3ubuntu1_amd64.deb 403 Forbidden
Failed to fetch http://us-west-1.ec2.archive.ubuntu.com/ubuntu/pool/main/p/pptpd/pptpd_1.3.4-3ubuntu1_amd64.deb 403 Forbidden
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?
私は何を間違っていますか？これは既知の問題ですか?