Trying to rip animations ends up in a mess :-(

First question: Did you turn your Ao off? there is a chance that the animation is on a low priority.

second question: No, some of the longer dances are broken into multiple parts, second life will only support an animation that is 59.9 seconds long.
sometimes the creators will either break the dance into parts, or they'll just put two short dances together to make one dance. If you followed Drebin's guide then you did everything right.