D'oh! Manual transmission in gear. I'm an idiot. Didn't say anything about that in the instructions!
As for not tightening the valve adjusting nut onto the lock nut, I ask because I may have forgotten to do that on one valve. Even though I couldn't turn the engine, one valve was in proper position to adjust and so I tried to adjust that one. I was having a hell of a time getting the wrenches in there and kept having to reposition myself. During one of my repositionings, I ended up with the wrenches on a different valve by accident. I may have loosened the lock nut a bit on that one before I realized it was the wrong one. I didn't bother to check it to to see if I had indeed loosened it because I was going to get to that one eventually for adjustment. But then I couldn't move the engine and never got to any of the other valves. I put everything back together, cleaned up, and then remembered that I might have loosened that other valve's lock nut. So I ask because I want to know if I should not run the car until I get back in there and tighten up that lock nut. I'm not certain that I actually loosened it, but it's certainly possible and I don't want to take any chances.