Using `saucy` or `precise` produced the same errors for me.

```
$ cat /etc/apt/sources.list | grep maven3
deb https://launchpad.net/~natecarlson/+archive/maven3 precise main
deb-src https://launchpad.net/~natecarlson/+archive/maven3 precise main

$ sudo apt-get update | grep maven3
W: Failed to fetch https://launchpad.net/~natecarlson/+archive/maven3/dists/precise/main/source/Sources  HttpError404
W: Failed to fetch https://launchpad.net/~natecarlson/+archive/maven3/dists/precise/main/binary-amd64/Packages  HttpError404
W: Failed to fetch https://launchpad.net/~natecarlson/+archive/maven3/dists/precise/main/binary-i386/Packages  HttpError404

E: Some index files failed to download. They have been ignored, or old ones used instead.
```

It kinda feels like this level of detail is outside the scope of the project. I think it would be fine to simply note that Maven 3.1+ is required and link to http://maven.apache.org/download.cgi.