When trying to update Ubuntu you might at some point run into 404 errors in the updater – the exact error might look like below:
Failed to download repository information
Check your Internet connection.
And if you open the details of the error message:
W:Failed to fetch http://ppa.launchpad.net/andphe/php/ubuntu/dists/precise/main/source/Sources 404 Not Found , W:Failed to fetch http://ppa.launchpad.net/andphe/php/ubuntu/dists/precise/main/binary-i386/Packages 404 Not Found , E:Some index files failed to download. They have been ignored, or old ones used instead.
The problem in it self should be harmless – but if you really want to get rid of it, just upen up your Software Sources in the software center. The Software Sources can be found in the software center, in the edit menu.
You can then find the URLs that are failing with a 404 error, and either remove them or simply uncheck them.