Flashback over database link

this morning I had to get some rows via flashback query. Since my undo retention is just 3h, the undo segments were already aged out. But I have a physical standby database that is mounted read only during daytime for report processing etc. On this one the old data is still available, but I was not able to pull them over to my primary site.
Here is what I tried:

create table hay_abos_20050309 as
(select * from dt_abo_bezug_at_standby as of timestamp

    to_date('08.03.2005 15:15','DD.MM.YYYY HH24:MI')  where mandantenkode='HAY');

ERROR at line 1:
ORA-25124: Database link name not allowed.

Okay, then I tried to use dbms_flashback but I was not able to call the procedure over a database link:

begin

   dbms_flashback.enable_at_time_at_standby(to_date('08.03.2005 15:21','DD.MM.YYYY HH24:MI'));
end;
/

ERROR at line 1:
ORA-02083: database name has illegal character '¹' ORA-06553: PLS-707: unsupported construct or internal error [2604]

I can call simple procedures over the database link but obviously calling packaged procedures this way gives an error.