Hey, I know this is pretty late for a post but I joined not long ago and saw this post while browsing.
I keep bees for a living so I have a fair amount of experience with beeswax. Shrinkage cracks are common when pouring large blocks of wax (like a bread loaf). It's pretty unusual to get shrinkage cracks while working with a regular small mold, although some shapes can be problematic. Don't know what you were pouring into so it's hard to comment.
GrayWolf had some good advice.
Beeswax is best poured at a temperature of about 170º. You don't want to overheat it and you should melt it in a double boiler; it's very flammable. Shrinkage cracks can usually be prevented by slowing the cooling process. I'll sometimes even warm my oven to 200º, turn it off, pour the wax, and put it into the oven to harden. (I generally don't do this except for big items or when pouring a 1# "block of wax" for our state honey show.)
Also, if you can't get the finished item out, spray with mold release beforehand. I like polyurethane molds because sticking is not an issue, and use them almost exclusively.