Capt. Potatoes

I just browsed 300 pages looking for anything about this, and couldnt find a definitive answer. I just DLthis pack, and when i build the Saturn V using the instructions in the parts descriptions it ends up looking correct, but upon launch, i fail every time, the rocket wiggles and wobbles/breaks at its joints or shortly after lift off, sometimes the engines do not even fire and i just drop... any help on this? am i missing something? orrrrr??