P0442 - EVAP System Small Leak Detected. The NVLD stands for Natural Vacuum Leak Detection. Sounds like they are saying you need a new NVLD vacuum switch. There are a handful of reasons this code can go off all of which relate to emissions. Loose gascap, A small leak/hole in a fuel vapor hose/tube, and so forth. Generally they'll do a smoke test to find where the leak is coming from, but the easiest thing to check first is the gas cap.
You can find more information at http://repairpal.com/OBD-II-Code-P0442. Hope this helps.