Mine occasionally throws up the Vehicle Protection System/Alarm not available. Can't replicate it to pin it down to a certain cause though. Battery excluded as it's been replaced recently.
As for the gearbox, mine did it a few times, scary thing that thud. Topping up with new (proper) oil sorted it for a while, but it seemed not enough. It came back later and long story short, my bank account cried. From memory of speaking to the guy who fixed my gearbox...
The K1 clutch (gears 1, 2, 3 & R) was not always engaging properly (hence the runaway revs) and when it did, it would slam into gear anywhere between 2-4k revs. This was caused by old or not enough oil. Obviously not good for the box. The knock on effect was that the K2 clutch eventually failed (that engages gears 4,5 & 6).
Based on my experience, I'd get it to an auto-mechanic asap so they can test it, flush and change the oil for you. The Q-Tronic isn't the easiest to work on yourself. The Volvo forums have some great info on them though. Sorry to scare you.