apt-get update not working

This is my first forum post ever on a tech forum - sorry in advance if I'm doing this all wrong.

I'm running 10.04 LTS and when I run "sudo apt-get update" I get the following:

Get:28 http://us.archive.ubuntu.com lucid-backports/multiverse Sources [1,633B]

Fetched 3,763kB in 2s (1,265kB/s)

W: Failed to fetch http://ppa.launchpad.net/nginx/php5/ubu … ackages.gz">http://ppa.launchpad.net/nginx/php5/ubuntu/dists/lucid/main/binary-i386/Packages.gz 404 Not Found

E: Some index files failed to download, they have been ignored, or old ones used instead.

Any ideas how to fix this?

Thanks,

Andrew