Comment 4 for bug 370454

It looks like the problem starts when it retains libkipi0, rather than replacing it with libkipi6.

The upgrade tool will have rolled back when it failed, so you won't be able to see the errors in synaptic normally. if you want to see what it's trying to do, you'll have to start the upgrade one way or another, so that it replaces 'intrepid' with 'jaunty' in /etc/apt/source.list, and then gets the new package lists. If you can stop it after that stage, then look at a package manager to see what it's trying to do... This is obviously something to try if you're comfortable mucking around with your system a bit.