allocation parameter <num> overflows when rounded

  Explanation:  the allocation parameter selected, though  it  may
  be  an  allowed  value,  becomes illegal when rounded to make an
  even number of pages in the storage area; i.e.,  the  number  of
  pages  to  actually  be  allocated  is  always a multiple of the
  number of pages per buffer

  User Action:  select a smaller allocation parameter.