RE:drillingSoulfire. I've been on a rig while doing fishing operations so can maybe answer some of your questions.
I guess it's reasonably common, I would say 1 in 4 offshore wells might have some operational difficiulties like this. It's very easy to do when you're drilling somewhere new with unexpected pressure differentials. Maybe others might disagree with this, I have nothing really to back this up apart from gut feel on a small sample size.
Who pays? It depends. Usually the operator. So they are paying for the rig time, and probably to replace the tool they've lost.
I don't know the details of the well or what they've lost, and how, but we're talking about retrieving something 1000's of feet/metres away with some weird tools. I was told you're doing the equivilent of putting a string through a needle using your teeth.
Anyway, hopefully they can wrap things up quickly and the rig to move on to more important things! :)