create or replace library libc_l as 'c:\windows\system32\crtdll.dll';

create or replace package random_utl
as
  function rand return pls_integer;
  pragma restrict_references (rand, WNDS, RNDS, WNPS, RNPS);
 
  procedure srand (seed in pls_integer);
  pragma restrict_references (srand, WNDS, RNDS, WNPS, RNPS);
end random_utl;
 
create or replace package body random_utl
as
  function rand return pls_integer
    is
      external
      library libc_l
      name "rand"
      language c;

  procedure srand (seed in pls_integer)
    is
      external
      library libc_l
      name "srand"
      language c
      parameters (seed ub4);

end random_utl;

SID_LIST_LISTENER =
  (SID_LIST =
    (SID_DESC =
      (SID_NAME = PLSExtProc)
      (ORACLE_HOME = C:\oraclexe\app\oracle\product\10.2.0\server)
      (ENV = "EXTPROC_DLLS=ANY")
      (PROGRAM = extproc)
    )
    (SID_DESC =
      (SID_NAME = CLRExtProc)
      (ORACLE_HOME = C:\oraclexe\app\oracle\product\10.2.0\server) 
      (PROGRAM = extproc)
      (ENV = "EXTPROC_DLLS=ANY")
    )
  )

EXTPROC_DLLS=C:\windows\system32\crtdll.dll

create or replace procedure external_dll_sp
as
  rnd_value pls_integer;
  seed pls_integer;
begin
  select to_char(sysdate, 'SSSSS') into seed from dual;
  random_utl.srand (seed);
  for v_cnt in 1 .. 10 loop
    rnd_value := random_utl.rand;
    dbms_output.put_line ('rand() call #' || v_cnt || ' returns ' ||
rnd_value);
  end loop;
end;

Connecting to the database new_test.
ORA-28595: Extproc agent : Invalid DLL Path
ORA-06512: at "NEW_TEST.RANDOM_UTL", line 10
ORA-06512: at "NEW_TEST.EXTERNAL_DLL_SP", line 7
ORA-06512: at line 2
Process exited.
Disconnecting from the database new_test.