Just wondering if you can tell me how serious of a problem is it when the check engine light comes on?

The reason I ask is because currently I am in another city on a business trip and the check Engine light came on my 1999 CLK. As I usually prefer to take to one shop (which is in my home town), I would like to know if I can keep drivign my car for about 10 days more and then take it to the dealership where they have my complete maintenace records and everything to look at the car.

Any ideas?

as long as the car is running alright there shouldn't be any problem. the check engine light is mainly focused on emissions related failures. so while you may not be as eco-friendly as normal, the car itself should be alright.