2002 VW Jetta VR6

Recently did an engine scan and these are the codes that were found:

16712 Knock Sensor 1 Circ High Input
16717 Knock Sensor 2 Circ High Input
16724 Camshaft Pos. Sensor (a) Circ Incorrect allocation
16804 Catalyst System, Bank 1 Efficency below threshold

I have no idea what these codes mean (layman's terms). Can I correct these codes or would I be better off taking it to a local VW mechanic? I have a pretty good mechanical aptitude. I erased all the codes but this one came back (16724 Camshaft Pos. Sensor (a) Circ Incorrect allocation). There does seem to be an uncommon noise coming from the engine. When I took it for a spin the noise is amplified when accelerating but almost nonexistent when idling(real bad rattle). There is no power when taking off either. My scanner is pretty basic all I get is the 5 digit code and then look up the meaning on the internet.

Thanks

First Knock Sensor: It allows the engine to run with the ignition timing as far advanced as possible. The computer will continue to advance the timing until the knock sensor detects pinging. At that point the computer retards the ignition timing just enough for the pinging to stop.
A knock sensor assures that you're getting as much power and fuel economy as is possible from your engine.
The sounds you here is most likely pinging and knocking(which is damaging to your engine) from improper fuel detenation and also your loss in power.
Camshaft pos sensor and Catalyst System.
Most likely, but not exactly related to Knock Sensor. I would first do the Knock Sensor and it might clear all other codes. That's the do it yourself side.
My expert take would be to run it up to your nearest VW dealer and let them do a full VAG-COM scan. It it is a absolute scan and will get your VR6 in top condition. Hope this helps!
Franco