More Questions on the Building a Bigger Engine Program

I just did my first workout, Build a Bigger Engine, and it was tiring. I did it at 10pm, my only time to workout. I can’t get up in the morning early enough. My questions about the routine are:

1) Is it ok I can only do 4 pullups max at this point. I was never strong at them.

2) I don’t have a preacher curl is there anything else you would suggest? I was doing 1 arm dumbbell preacher curl on an incline bench.

3) The pushups didn’t tax me a lot. Should I do till failure? Or what would you suggest?

Thank You,
D.S.

My Answer: It's supposed to be tiring. Fat loss programs usually are tiring. If it was easy, then you wouldn't losing much fat, would you? Anyway, to answer your questions:

1) Yes

2) One arm dumbbell preacher curls at the top of an incline bench are fine.

3) It says right there in the program, "Pushups... as many reps as possible." That means go to failure.