The Epc light and the engine light are on, what does that mean

There are several possibilities... In reality it means the vehicle needs a professional scan test to help find the problem that's turned those lights on... Can guess at it from now on and be wrong every time! .. If engine performance seems to be pretty much normal, ok to drive to repair shop for testing.

It could be many things, here are some you might want to try, but you should talk to a mechanic: http://www.startmycar.com/volkswagen/jetta/problems/spark-plugs