The DSC light could well be related to the fault, I suggest that you either get the codes read by a good indy with the Jaguar software or buy a reader on line and retrieve, the codes yourself
very pleased with my Memoscan, all the family and friends use it on different cars. Works well.DSC not available on startup could be a sign of low battery voltage - could yours do with a bit of a charge? Regarding the reader - I've got a Memoscan U581 that I'm happy with although lots of people on here use ELM ones and their laptop or android phone. There's a recent thread about them on one of the forums, and there have been loads in the past.