Ada Pointer Problem

[aschwarz@acm.org (skidmarks)]

Each Ptr assignment below yields the following error message:

--    9.    Ptr     : a.X_Ptr  := Object'Access;
--       non-local pointer cannot point to local object

In the past, the only way that I seem to be able to fix the problem is to
put the pointer and assignment in global space (either in file global or
in a package spec). I've looked at Ada as a Second Language (Cohen) and, 
with less diligence, at the Ada LRM but can't figure what I'm doing wrong. 
What am I doing wrong?

thanks
art

-----------------------------------------------------------
-----------------------------------------------------------

package a is
   type X     is new Integer;
   type X_Ptr is access all X;
end a;

--------------------------------------------------------

-- Main Program

with a;

Procedure b is
   subtype Y         is a.X;
   subtype Y_Ptr     is a.X_Ptr;

   Object  : aliased a.X;
   Object_Y: aliased Y;
   Ptr     : a.X_Ptr  := Object'Access;
   Ptr_Y   : Y_Ptr    := Object'Access;
   Ptr_OY  : a.X_Ptr  := Object'Access;
   Ptr_1Y  : Y_Ptr    := Object'Access;

begin -- b
   Ptr     := Object'Access;
   Ptr_Y   := Object'Access;
end b;