Okay so lets look at this using apples. First you have 30 apples and 0 groups. Now you want to divide the 30 apples into 3 and then dispurse them evenly in the groups of 0. The key here is the groups. No matter how many apples we have we cannot put them into groups of zero. So we are left with a group of zero.

As terr said its rather simple in calculus.

Lets take 1 and divide it by a number lets say .5. Now if .5 approaches 0 it will gradually increase the answer therefore approaching infinity. So i see your point or at least the point i hope you are trying to make which is a good one.

Lets take a book, throw it in ther air and it will most definetly hit the ground right. No argument there.....unless you are using a limit which says that the book cannot actually hit the floor because if we take the distance and gradually approach it to zero (zero of course being the floor) then the distance can be infinetly divided to become closer and closer to the floor. So if this were true then it never really did hit the floor its still just getting closer and closer.
The reason for this error is that calculus is an aproximation used to define things un-explainable...to try and approach or get a close as we can to the answer. It is lets say 99.99 percent true