It can be very easy to accidently mix up the plug wire routing. It happened to me on my own car when I changed the plugs for the first time. I had accidently swapped the 1 and 3 wires. Others have posted that they have done the same thing. With a little bit of a search you should fid a recent post that provides the correct plug wire routing.
By the way, I spent about 15 years of my life as a tune up mechanic and seldom had this problem. If I can make this mistake, then anyone can.
