C Puzzle #7

If you will execute this program on a 32 bit computer (IA 32), it will execute smoothly. But what is the problem with 64 bit computers(IA 64).

int main()

  {

      int* p;

      p = (int*)malloc(sizeof(int));

      *p = 10;

      return 0;

  }

It would be worth to check answer