You should be able to get at least a couple hundred cuts on a plate--but that is with flipping it and cutting on all different parts of it. If all your cuts were in one spot, then even embossing may have cracked it. If you've only been embossing, then the plates definitely shouldn't have cracked at all.
Some of the original plates were defective. So call Provo Craft (1.800.937.7686) and see if they'll send you a replacement.
I've used my Bug quite a bit since Christmas, and just this week cracked the second of that first set of plates.
I don't know if mine were defective or just used up! LOL I already had some backup plates, so I've just been using those.