It seems as if you are attempting to downgrade a database - at least,
that's what my Google-fu turns up - but I don't have a very high
Google-fu rating! ;-)

There's a tracker on this very matter at
http://tracker.firebirdsql.org/browse/CORE-2949.


Cheers,
Norm.

--
Norman Dunbar
Dunbar IT Consultants Ltd

Registered address:
27a Lidget Hill
Pudsey
West Yorkshire
United Kingdom
LS28 7LG

Company Number: 05132767