Problem upgrading 10.04 to 12.04

[stan]

I upgraded my laptop from 10.04 to 12.04 yesterday, and all went well. So,
I decided to upgrade one of the workstations at work. 

However this upgrade fails to start. It generates the following error
message early in the process, and then aborts completely:

:Failed to fetch 
http://ppa.launchpad.net/pitti/postgresql/ubuntu/dists/precise/main/binary-amd64/Packages

404 Not Found 

Looks like there is a missing file?

What can I do to resolve this?

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