2002 Audi A4 About the timing belt etc.

I have an audi 2002 a4. I replaced my timing belt using the camshaft locker(were it puts the cams in in there actual position). While I was doing that I also replaced my spark plugs. When I started the car it showed these symptoms; Rough running, loss of engine power, and kind of hard to start but not realy. I checked the car and its showing me P0340 (camshaft disposition malfunction). Could it be a disposition of the belt or something dealing with sensors or the electricity?